Bug 2186: Close socket when ns_memcached terminates.
Bug 2186: Close socket when ns_memcached terminates.

Otherwise, if it crashes, we leak connections.

Change-Id: I94f1a6b1651184dea77aad5f72b850cccefb62d2
Reviewed-on: http://review.northscale.com/2088
Reviewed-by: Dustin Sallings <1c08efb9b3965701be9d700d9a6f481f1ffec3ea@spy.net>
Tested-by: Dustin Sallings <1c08efb9b3965701be9d700d9a6f481f1ffec3ea@spy.net>

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