MB-10934 make upr_sup to kill the replicators for nodes that are not

...in the list of desired reps. This makes upr replicators to work
similar to tap replicators which do not expect {Node, []} to be in
the list in order to kill the replicator.

Change-Id: Iaa99b3df9c6ddfed8de20eacd2ad6367a6eb189f
Reviewed-on: http://review.couchbase.org/36287
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>