[rel-3.0.2] update ns_server to rel-3.0.0++ branch

Change-Id: Id4de4b26dc71277a7bd3e48494c18bfee6d95dd0
Reviewed-on: http://review.couchbase.org/43008
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>