Converting ns_server to CMake.

Change-Id: If73a693b546e3f22ef902af2d385024cc38911fa
Reviewed-on: http://review.couchbase.org/34759
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>