FCPClientReferenceImplementation: Remove serial version from never
serialized stuff
DebugFCPClient: Correct logging/comments

- We do not validate the existing data against the additional
synchronization, we merely correct it from it.
- There currently is no mechanism for triggering re-synchronization, so
this event should be logged as warning, not normal.
DebugFCPClient: Remove obsolete class

Synchronization is now handled by
BeginSubscriptionSynchronizationHandlerImpl,
EndSubscriptionSynchronizationHandlerImpl and
SubscribedObjectChangedHandlerImpl