Diffusion - fix T3215
Summary: Ref T2784. We need to always return array() here so the foreach doesn't crap out
Test Plan: chad - can you confirm this fixes the error? I have ref-heavy git repos it seems. should work though.
Reviewers: chad, epriestley
Reviewed By: chad
CC: aran, Korvin
Maniphest Tasks: T3215, T2784
Differential Revision: https://secure.phabricator.com/D5961