Do not unregister ns_memcached data instances
Do not unregister ns_memcached data instances

Per http://review.couchbase.org/14179

Change-Id: I1f49c1a706b937b898d4df738eb5ea4595e540c6
Reviewed-on: http://review.couchbase.org/14372
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Tested-by: Srinivas Vadlamani <4036f57732a648e71da3ac2c829c8239a16a4c5d@couchbase.com>

vzasade/ns_server,membase/ns_server,daverigby/ns_server,pavel-blagodov/ns_server,t3rm1n4l/ns_server,membase/ns_server,pavel-blagodov/ns_server,vzasade/ns_server,vzasade/ns_server,nimishzynga/ns_server,ceejatec/ns_server,membase/ns_server,mschoch/ns_server,ceejatec/ns_server,ceejatec/ns_server,membase/ns_server,membase/ns_server,mschoch/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,daverigby/ns_server,nimishzynga/ns_server,membase/ns_server,daverigby/ns_server,mschoch/ns_server,vzasade/ns_server,nimishzynga/ns_server,daverigby/ns_server,mschoch/ns_server,daverigby/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,nimishzynga/ns_server,mschoch/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,pavel-blagodov/ns_server,ceejatec/ns_server