Fix 500 error when commiting with no changes

org.eclipse.jgit.api.errors.JGitInternalException: Updating the ref HEAD to AnyObjectId[2b0f6df9857d6bb1e3ce11af15b376fe5cf19ffc] failed. ReturnCode from RefUpdate.update() was NO_CHANGE
	at org.eclipse.jgit.api.CommitCommand.call(CommitCommand.java:303) ~[org.eclipse.jgit-5.9.0.202009080501-r.jar:5.9.0.202009080501-r]
	at com.nuxeo.studio.core.GitServiceImpl.commit(GitServiceImpl.java:390) ~[nuxeo-studio-core-4.4.2.jar:?]
	at com.nuxeo.studio.core.GitServiceImpl.saveWIP(GitServiceImpl.java:420) ~[nuxeo-studio-core-4.4.2.jar:?]
	at com.nuxeo.studio.core.utils.SaveStrategyUtils.performSave(SaveStrategyUtils.java:63) ~[nuxeo-studio-core-4.4.2.jar:?]
	at com.nuxeo.studio.web.v2.wsadapters.ResourcesWorkspaceAdapter.uploadResource(ResourcesWorkspaceAdapter.java:85) ~[nuxeo-studio-web-4.4.2.jar:?]
	at sun.reflect.GeneratedMethodAccessor1322.invoke(Unknown Source) ~[?:?]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_282]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_282]
	at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.SubLocatorRule.accept(SubLocatorRule.java:137) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.SubLocatorRule.accept(SubLocatorRule.java:137) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.SubLocatorRule.accept(SubLocatorRule.java:137) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.SubLocatorRule.accept(SubLocatorRule.java:137) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1542) ~[jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1473) [jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1419) [jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1409) [jersey-server-1.19.4.jar:1.19.4]
	at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:409) [jersey-servlet-1.19.4.jar:1.19.4]
	at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:558) [jersey-servlet-1.19.4.jar:1.19.4]
	at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:733) [jersey-servlet-1.19.4.jar:1.19.4]
	at org.nuxeo.ecm.webengine.app.jersey.WebEngineServlet.containerService(WebEngineServlet.java:72) [nuxeo-webengine-core-10.10-HF30.jar:?]
	at org.nuxeo.ecm.webengine.app.jersey.WebEngineServlet.service(WebEngineServlet.java:56) [nuxeo-webengine-core-10.10-HF30.jar:?]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) [servlet-api-9.0.41.jar:4.0.FR]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-websocket-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.elasticsearch.ElasticSearchFilter.doFilter(ElasticSearchFilter.java:59) [nuxeo-elasticsearch-core-10.10-HF39.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.webengine.jaxrs.session.SessionCleanupFilter.run(SessionCleanupFilter.java:50) [nuxeo-webengine-jaxrs-10.10-HF08.jar:?]
	at org.nuxeo.ecm.webengine.jaxrs.HttpFilter.doFilter(HttpFilter.java:49) [nuxeo-webengine-jaxrs-10.10-HF08.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.webengine.app.WebContextFilter.doFilter(WebContextFilter.java:56) [nuxeo-webengine-core-10.10-HF30.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.webengine.jaxrs.context.RequestContextFilter.run(RequestContextFilter.java:48) [nuxeo-webengine-jaxrs-10.10-HF08.jar:?]
	at org.nuxeo.ecm.webengine.jaxrs.HttpFilter.doFilter(HttpFilter.java:49) [nuxeo-webengine-jaxrs-10.10-HF08.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.webengine.app.HeaderFixFilter.run(HeaderFixFilter.java:62) [nuxeo-webengine-core-10.10-HF30.jar:?]
	at org.nuxeo.ecm.webengine.jaxrs.HttpFilter.doFilter(HttpFilter.java:49) [nuxeo-webengine-jaxrs-10.10-HF08.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at com.nuxeo.connect.filter.SudoFilter.doFilter(SudoFilter.java:60) [nuxeo-connect-plugin-we-4.4.2.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at com.nuxeo.connect.filter.ConnectUrlFilter.doFilter(ConnectUrlFilter.java:111) [nuxeo-connect-plugin-we-4.4.2.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at com.nuxeo.studio.core.auth.StudioWebFilter.run(StudioWebFilter.java:62) [nuxeo-studio-core-4.4.2.jar:?]
	at org.nuxeo.ecm.webengine.jaxrs.HttpFilter.doFilter(HttpFilter.java:49) [nuxeo-webengine-jaxrs-10.10-HF08.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.web.common.requestcontroller.filter.NuxeoThreadTrackerFilter.doFilter(NuxeoThreadTrackerFilter.java:43) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.web.common.requestcontroller.filter.NuxeoStandbyFilter.doFilter(NuxeoStandbyFilter.java:67) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.core.management.jtajca.internal.Log4jWebFilter.doFilter(Log4jWebFilter.java:69) [nuxeo-core-management-jtajca-10.10.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.ui.web.rest.FancyURLFilter.doFilter(FancyURLFilter.java:120) [nuxeo-platform-ui-web-10.10-HF41.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.web.common.idempotency.NuxeoIdempotentFilter.doFilter(NuxeoIdempotentFilter.java:114) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at javax.servlet.http.HttpFilter.doFilter(HttpFilter.java:57) [servlet-api-9.0.41.jar:4.0.FR]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.web.common.requestcontroller.filter.NuxeoRequestControllerFilter.doFilter(NuxeoRequestControllerFilter.java:134) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.ui.web.auth.NuxeoAuthenticationFilter.doFilterInternal(NuxeoAuthenticationFilter.java:640) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.nuxeo.ecm.platform.ui.web.auth.NuxeoAuthenticationFilter.doFilter(NuxeoAuthenticationFilter.java:431) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:209) [cors-filter-2.6.jar:2.6]
	at com.thetransactioncompany.cors.CORSFilter.doFilter(CORSFilter.java:244) [cors-filter-2.6.jar:2.6]
	at org.nuxeo.ecm.platform.web.common.requestcontroller.filter.NuxeoCorsCsrfFilter.doFilter(NuxeoCorsCsrfFilter.java:258) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.web.common.exceptionhandling.NuxeoExceptionFilter.doFilter(NuxeoExceptionFilter.java:67) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.nuxeo.ecm.platform.web.common.encoding.NuxeoEncodingFilter.doFilter(NuxeoEncodingFilter.java:64) [nuxeo-platform-web-common-10.10-HF40.jar:?]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.valves.rewrite.RewriteValve.invoke(RewriteValve.java:289) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [catalina-9.0.41.jar:9.0.41]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [catalina-9.0.41.jar:9.0.41]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) [tomcat-coyote-9.0.41.jar:9.0.41]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-coyote-9.0.41.jar:9.0.41]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:888) [tomcat-coyote-9.0.41.jar:9.0.41]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1597) [tomcat-coyote-9.0.41.jar:9.0.41]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-coyote-9.0.41.jar:9.0.41]
	at datadog.trace.bootstrap.instrumentation.java.concurrent.Wrapper.run(Wrapper.java:25) [?:0.75.0]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_282]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_282]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util-9.0.41.jar:9.0.41]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_282]