OPENDJ-3133 dsreplication status reports M.C. (Missing Changes) when none exist

ReplicaOfflineMsg where incorrectly updating the server state of replicas (DSs).
The fix consists in ensuring the server state are not updated
while still allowing ReplicaOfflineMsgs to be forwarded to the topology.

The proposed change allow ServerWriter.run() to forward ReplicaOfflineMsgs
to other Replication Servers in the topology.

Side-note: here is the call hierarchy showing how the current change still allows ReplicaOfflineMsgs to be forwarded:
org.opends.server.replication.server.MessageHandler.updateServerState(UpdateMsg)
org.opends.server.replication.server.MessageHandler.getNextMessage()
org.opends.server.replication.server.ServerHandler.take()
org.opends.server.replication.server.ServerWriter.run()