MB-100: fix replication_while_rebooting_a_non_master_destination_node

http://qa.hq.northscale.net/job/centos-64-2.0-uniXDCR-biXDCR-sanity/400/consoleFull

Change-Id: I6440940f1e135acdc189c31a497b216e8563620b
Reviewed-on: http://review.couchbase.org/24849
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>