MB-9343 make sure that all old upr consumer connections are killed

.. before janitor_agent queries vbucket states the first time

Change-Id: Iceb7b16d6f313b2ffd3ccad17e825bf8d5fcc811
Reviewed-on: http://review.couchbase.org/34250
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>