MB-11928: increased janitor apply config timeout for rebalance

Change-Id: If8a453fe173775eab700c9f1a259911920f5bd77
Reviewed-on: http://review.couchbase.org/40605
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>