The local check prefers underscored file names.

We used to look for a local check script in `config/pre-commit.rb`.
All of the dashes generally come from Git's usage of the `pre-commit`
hook.

However, not everyone uses dashes in their filenames. The local check
will now look for (and prefer `config/pre_commit.rb` over
`config/pre-commit.rb`)
Merge pull request #184 from jish/josh/local_check_prefers_underscores

The local check prefers underscored file names.