Fix operator error in Pholio with PHP 7.1
Summary: Fixes T12166. We don't actually need this variable, so removing it.
Test Plan: Upload a new mock, edit a mock, view list of mocks.
Reviewers: epriestley, Mnkras, acs-ferreira
Reviewed By: epriestley, Mnkras, acs-ferreira
Subscribers: acs-ferreira, Korvin
Maniphest Tasks: T12166
Differential Revision: https://secure.phabricator.com/D17260