Fix redirects in Phragment

Summary: This fixes the ZIP controller redirect in Phragment after the external redirect change.

Test Plan: Tested it on my server.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin, hach-que

Differential Revision: https://secure.phabricator.com/D10350