ISPN-2885 Expose parameter names in MBean metadata
ISPN-2883 Use special naming to overcome JMX method overloading with RHQ
operation name uniqueness
ISPN-2787 NPE after ReplaceCommand

* Add MergeDuringReplaceTest to reproduce the issue.
* Fix one of the ControlledRpcManager.invokeRemotely methods that was ignoring the actual result and was always returning null.
* Minor logging improvements to be able to debug this issue.
* Remove harmfull optimization from RpcManagerImpl.invokeRemotely(Collection<Address> recipients, ReplicableCommand rpcCommand, ResponseMode mode, long timeout, boolean usePriorityQueue, ResponseFilter responseFilter) that was not going remotely and neither threw any exception if the destinations were no longer in cluster and current node was the only member.