Summary: First, I broke the addIcon() call recently with bad greps. Second, a user is reporting an issue on GitHub (https://github.com/facebook/phabricator/issues/346) which I can't reproduce but which could reasonably occur for various reasons. Don't depend on being able to find the source/target of a move. Test Plan: Looked at recent updates in Phriction. Reviewers: btrahan Reviewed By: btrahan CC: aran, seungrye Differential Revision: https://secure.phabricator.com/D6389