ISPN-2589 NPE in InvalidateL1Command 

This NPE can appear in both DIST and REPL mode when we process a topology update in which the current node is not a member.  

 * There is no reason to invalidate segments if we are not a member, so the call to StateConsumerImpl.invalidateSegments() is guarded with a membership check. This also avoids the NPE.
 * StateConsumerImpl.invalidateSegments() was wrongly using CommandsFactory.buildInvalidateFromL1Command where it should actually be buildInvalidateCommand()
 * Extract all the logic to restart broken transfers from failed sources into a separate method (StateConsumerImpl.restartBrokenTransfers()) 
* Rename StateConsumerImpl.notifyEndOfTopologyUpdate() to notifyEndOfRebalanceIfNeeded() to clarify its purpose
 * Remove StateConsumerImpl.activeTopologyUpdates member as all the logic regarding it has long become redundant 
 * Remove one of the overloaded variants of CommandsFactory.buildInvalidateFromL1Command that is no longer used

Please integrate in master. 

JIRA: https://issues.jboss.org/browse/ISPN-2589