cmdserver: include non-zero return code of runcommand in test output

cmdserver: recreate mq object on runcommand in case queue path was changed repo.mq needs to be recreated after queue path change. Since there is little benefit to keep invalidated mq object, it always delete repo.mq.

cmdserver: reload mq on each runcommand request to avoid corruption If mq was changed by another process, command server should invalidate caches. Otherwise, mq status would go wrong.