MB-11928: added timeout to janitor_agent's apply config call

Change-Id: I65a4529728803f179b448a578fd3d52cacfc0e3b
Reviewed-on: http://review.couchbase.org/40604
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>