Fix several issues with "Logout"
Summary:
Ref T1536.
- When we render a dialog on a page by itself, put it on a dust background.
- Currently, we render "Logout" in two different places. Stop doing that.
- Make sure the surviving one has workflow so we get a modal ajax dialog if possible.
Test Plan: {F46731}
Reviewers: chad, btrahan
Reviewed By: chad
CC: aran
Maniphest Tasks: T1536
Differential Revision: https://secure.phabricator.com/D6226