MB-9343 nuke upr connections if the rebalance was stopped or failed.

the connections will be nuked
- if the replicator crashed
- if the rebalance didn't succeed
- if the janitor_agent crashed during the rebalance

Change-Id: I6cbc0323512a59866ef0e19cff80a9eb4f25ef65
Reviewed-on: http://review.couchbase.org/34069
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>