Set an explicit default value for the bulk action control
I'm not sure if this is what the user is seeing, but in Chrome, the <select /> does not automatically get set to the first valid value like it does in Safari.
Set it to the first valid value explicitly.
Test Plan: In Chrome, bulk editor previously hit a JS error when trying to read a bad action off the <select />. After patch, bulk edits go through cleanly.
Reviewed By: amckinley
Maniphest Tasks: T13025
Differential Revision: https://secure.phabricator.com/D18923