[rel-2.5.0] bump ns_server reference for MB-9975 and MB-9984

Change-Id: I7438cf5d3d6a67fca7e9e184428f01c747f25389
Reviewed-on: http://review.couchbase.org/32750
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>