R1:86063d3fa7f5

Don't hide filename in filetree on hover

Summary:
It currently looks like this:

{F21417, size=full}

Test Plan: Hovered file name in filetree.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3729