MB-6865: Allow delete to return TMP_FAIL
MB-6865: Allow delete to return TMP_FAIL

Delete needs to return TMP_FAIL when the underlying engine is
running in degraded mode.

Change-Id: I70e589a069d51a2145ae27c82c25b8768c52ba71
Reviewed-on: http://review.couchbase.org/21661
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>

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