Fix startup of OpenSocial container since 6.0-HF11

ERROR [localhost-startStop-1] [org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/nuxeo]] Exception sending context initialized event to listener instance of class org.nuxeo.runtime.deployment.NuxeoStarter
java.lang.ExceptionInInitializerError
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
        at java.lang.Class.newInstance(Class.java:379)
        at org.nuxeo.osgi.BundleImpl.getActivator(BundleImpl.java:281)
        at org.nuxeo.osgi.BundleImpl.start(BundleImpl.java:300)
        at org.nuxeo.osgi.BundleRegistry.doRegister(BundleRegistry.java:179)
        at org.nuxeo.osgi.BundleRegistry.register(BundleRegistry.java:127)
        at org.nuxeo.osgi.BundleRegistry.install(BundleRegistry.java:99)
        at org.nuxeo.osgi.OSGiAdapter.install(OSGiAdapter.java:190)
        at org.nuxeo.osgi.application.loader.FrameworkLoader.install(FrameworkLoader.java:265)
        at org.nuxeo.osgi.application.loader.FrameworkLoader.doStart(FrameworkLoader.java:220)
        at org.nuxeo.osgi.application.loader.FrameworkLoader.start(FrameworkLoader.java:112)
        at org.nuxeo.runtime.deployment.NuxeoStarter.start(NuxeoStarter.java:121)
        at org.nuxeo.runtime.deployment.NuxeoStarter.contextInitialized(NuxeoStarter.java:89)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4994)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5492)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
        at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:672)
        at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1861)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: Runtime not initialized
        at org.nuxeo.runtime.api.Framework.checkRuntimeInitialized(Framework.java:531)
        at org.nuxeo.runtime.api.Framework.getProperty(Framework.java:365)
        at org.nuxeo.ecm.webengine.gwt.GwtBundleActivator.<clinit>(GwtBundleActivator.java:48)
        ... 29 more