CBQE-0: log message improvement for add_remote_cluster, start_replication

Change-Id: I4691c561dd5142103595ea265d3c60be120b9897
Reviewed-on: http://review.couchbase.org/36972
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>
Tested-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>