OF-2105: Don't depend on PEP service to be cached for removal.
The existing implementation of removal of a PEP service (which gets triggered if the owning user gets deleted) only operates on PEP services if they're currently in a cache.
Even if the PEP service is not currently cached, it should be deleted.
OF-2039: When processing CAPS changes, consider subscribed-to PEP nodes
Apply changes to notification filtering not only to PEP nodes that belong to the service owned by the sender, but also to those that the sender subscribes to.
OF-2102: Prevent incorrect shutdown of pubsub persistence provider
Do not shut down the persistence infrastructure when just one (of potentially many) pubsub services shuts down.
This commit depends on the previous commit, in that that commit now ensures that the persistence infrastructure is shut down when appropriate.
