URL Rewriter: in 7.8 no need to invoke invoke EventListenersContainer#start() again by Spring config

There was a report that on 7.8, the URL rewriter produced a stacktrace
"RepositoryException: failed to retrieve state of intermediary node for entry: 29941861-c9af-45c4-b104-98df161c757b, path: hippo:configuration /hippo/users/configuser

It was solved by removing EventListenersContainer#start() call in the Spring config.

Please check if this solution is correct and if so, update the example Spring config in the demo project.

See mail thread "URL rewriter plugin with Hippo 7.8.4 (Enterprise) gives exception" on hippo-community, https://groups.google.com/forum/#!topic/hippo-community/qGqTqGHrES0