R1:7368859d8df0

Properly set project icon in timeline

Summary: This fixes a bug where the icon won't display since it doesn't include `fa-`.

Test Plan: Change icon on a project, revisit timeline and see icon.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D16512