atom/atom — pull request #4755 by maxbrunsfeld (2014-12-24 00:30:17+00:00)
Title: Fix recurring errors when a non-existent package is disabled

Two problems:
* `PackageManager::activatePackage` throws an error when disabling a non-existent package. It should probably just reject its promise.
* `Config` observers get into a bad state when callbacks throw exceptions.