Lokaltog/powerline — pull request #489 by ntkme (2013-05-11 02:42:46+00:00)
Title: Fix vcs error when open files in git submodule

Fix the following error when the git dir is separated from the git work tree:
```
file_vcs_status:Exception while computing segment: [Errno 20] Not a directory: '/path/to/a-git-repo/.git/info/exclude'
```