Description of problem:
If there is any extraneous file in /var/lib/glusterd/$volname, deleting the volume will not delete that folder.  This in turn will make glusterd refuse to start the next time that is required.

Steps to Reproduce:
1. Put an extraneous file (such as run/swift.pid) into the volume directory.
2. Stop and delete the volume.
3. Restart glusterd.
  
Actual results:
Glusterd will not start, because it sees a volume directory and cannot find the info file.

Expected results:
It should allow startup (with logged warnings/errors) when it discovers that none of the expected files are in the volume directory.  If some of the files exist but others don't, it would be appropriate to not allow startup.  If a startup is allowed when a volume directory exists but none of the volume files exist, it may be a good idea to require additional action (after manually deleting the directory and any files it may contain) before a volume with the same name can be created.  Perhaps some special cleanup or force option on the delete command.  I leave that in your capable hands.

Additional info:
The specific file that seems to have caused this is a pid file from gluster-swift:
/var/lib/glusterd/vols/$volname/run/swift.pid