Clean up another insufficiently-general exception
Summary:
Ref T11044. This is still catching the older exceptions, which are now more general.
If you loaded the web UI without MySQL running, this meant you got a less-helpful error.
Test Plan: Stopped MySQL, loaded web UI, got a more-helpful error.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T11044
Differential Revision: https://secure.phabricator.com/D16930