mongoid/mongoid — pull request #1668 by rymai (2012-02-02 17:12:06+00:00)
Title: Ensure Mongoid.logger is not nil before calling warn on it.

Re-submit of #1666 but against `2.4.0-stable` this time! :)
---

Fix a `private method 'warn' called for nil:NilClass` issue.

Thanks!