R1:7dd31a16d973

Fix chatlog application query integration

Summary: `class_exists()` is case-insensitive, but `PhabricatorApplication::getByClass()` is not.

Test Plan: Fixed unit test to fail, then fixed code to pass unit test.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D7379