(stable) Fix an issue where "Close Revision" did not appear in the UI
Ref T2543. When called from the UI to build the dropdown, there's no Editor, since we aren't actually in an edit flow.
This logic worked for actually performing the edits, just not for getting the option into the dropdown.
Test Plan: Used the dropdown to close an "Accepted" revision which I authored.
Reviewed By: chad
Maniphest Tasks: T2543
Differential Revision: https://secure.phabricator.com/D18490