URL handlers not cleaned up

When someone try to hot re-deploy the nuxeo application, the new application get errors when accessing to URLs. The problem comes because we don't clear the handlers cache at the moment we're reinitializing the factory in URLStreamHandlerFactoryInstaller.installURLStreamHandlerFactory.

INFO: Illegal access: this web application instance has been stopped already. Could not load org.nuxeo.theme.protocol.nxtheme.Connection. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1273)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at org.nuxeo.theme.Manager$1.createURLStreamHandler(Manager.java:122)
at org.nuxeo.common.utils.URLStreamHandlerFactoryInstaller$FactoryStack.createURLStreamHandler(URLStreamHandlerFactoryInstaller.java:128)
at java.net.URL.getURLStreamHandler(URL.java:1106)
at java.net.URL.<init>(URL.java:572)
at java.net.URL.<init>(URL.java:464)
at java.net.URL.<init>(URL.java:413)
at org.nuxeo.theme.Manager.initializeProtocols(Manager.java:111)