Ensure Aphlict is served on the primary domain

Summary: This ensure that Aphlict is always served on the primary / production domain, because the alternate file domain is intended to prevent Flash execution.

Test Plan: Have not tested this at all.

Reviewers: #blessed_reviewers, joshuaspence, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9511