Use misc:is_normal_termination in ns_memcached...
Use misc:is_normal_termination in ns_memcached...

...module's terminate handler function.

Change-Id: I151e50a1ce5c67577c43d9b8b06de3c8d3f7a3b6
Reviewed-on: http://review.couchbase.org/89147
Tested-by: Ajit Yagaty <670a5cadfa9668cb910cc315f6527868cd5ab42a@couchbase.com>
Well-Formed: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Aliaksey Artamonau <ce14b1c16e0fd654f926118eb8addbec5aff4ffa@couchbase.com>

membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server