Fix mobile menus
Summary: The multiple icons are causing layout issues. This hides the unsused div (the real icon gets appended). We should probably clean this up next redesign.
Test Plan: test mobile layouts in Chrome, test main menu and application menu. Go to Differential, check those menus to.
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Differential Revision: https://secure.phabricator.com/D9086