facebook/arcanist — pull request #27 by phleet (2012-05-16 17:29:36+00:00)
Title: Make arc diff not crash on hg bookmarks

Using mercurial bookmarks and trying to run `arc diff` gave me this:

```
Exception:
Unknown Mercurial log field 'bookmark'!
(Run with --trace for a full exception trace.)
```

See: http://mercurial.selenic.com/wiki/BookmarksExtension

Not sure whether I should attach it to the `$commit` or just drop it - it isn't being used anywhere else right now