twitter/bootstrap — pull request #7643 by harrycheung (2013-04-20 05:04:18+00:00)
Title: Modal backdrop shouldn't be removed if it doesn't exist.

Fixed modal backdrop bug that was introduced with

https://github.com/twitter/bootstrap/commit/366e1e0a6d1442b8cf8546a27bac44a841b892a2

Check to make sure backdrop is used before removing it.

https://github.com/twitter/bootstrap/issues/7124