mxcl/homebrew — pull request #22142 by samueljohn (2013-08-27 08:30:31+00:00)
Title: Don't consider files in the Cellar as Racks

Otherwiese a `Cellar/.DS_Store` may lead to an error about
`.ds_store.rb` not found during `brew upgrade`.

For reviewers: Is the `if rack.directory?` the best option
with respect to performance? Any idea how to only list
directories and symlinks to directories?