MB-11360: Don't ack successful mutations
MB-11360: Don't ack successful mutations

Change-Id: I2b09fc07a2063a53d82e10477c500be1bed88847
Reviewed-on: http://review.couchbase.org/38068
Reviewed-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>
Tested-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>

couchbase/memcached,owendCB/memcached,mrkwse/memcached,cloudrain21/memcached-1,daverigby/memcached,daverigby/kv_engine,mrkwse/memcached,couchbase/memcached,owendCB/memcached,cloudrain21/memcached-1,owendCB/memcached,daverigby/memcached,couchbase/memcached,daverigby/memcached,daverigby/memcached,daverigby/kv_engine,jimwwalker/memcached,jimwwalker/memcached,couchbase/memcached,daverigby/kv_engine,mrkwse/memcached,mrkwse/memcached,cloudrain21/memcached-1,owendCB/memcached,daverigby/kv_engine,jimwwalker/memcached,cloudrain21/memcached-1