Fixes for Permissions and Secuirty Exceptions  

This merges all of 908898 fixes into head.  I'll pre screen this pull request to make sure it looks okay as its my first pull request on this repo.  Mainly it

- Updates GlusterFileSystem.setPermission to get the FileStatus and set permissions using Runtime.exec in the idiom used for apache's RawLocalFileSystem .
- Reintroduces the original FileInfoUtil class for getting owner  
- Adds a unit test for permissions 
-  Removes the working directory stuff which was messing absolute paths up.
-  Explicitly renames the temporary mount directory for making it easier to inspect privileges in unit tests ( /tmp/gluster is a little generic).