Cache tree structure for HttpSession replication does not consider virtual hosts

The tree cache structure used by JBossCacheManager/JBossCacheService for http session replication needs to include a level for virtual host.

The current Fqn pointing to a session's node is as follows:

/JSESSION/webapp_context_path/sessionid

This has the effect of mixing in the same subtree sessions from different webapps with the same context path but different virtual hosts. This leads to ClassNotFoundExceptions when the session expiration background processing thread tries to unmarshal sessions from a foreign webapp.

The Fqn structure should be as follows:

/JSESSION/virtual_host_name/webapp_context_path/sessionid