Treat unknown exit codes as error
Treat unknown exit codes as error

Change-Id: Ia9b119ea41b4b0230077cfc156d16e1490f07560
Reviewed-on: http://review.couchbase.org/30670
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

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