Fix double escaping in Pholio subscribers

Summary:
Fallout from D4822. We now escape text by default, and imploding links causes double-escaping. See here for details:

http://www.phabricator.com/docs/phabricator/article/Rendering_HTML.html

Test Plan: {F32100}

Reviewers: ljalonen, chad, btrahan, vrana

Reviewed By: ljalonen

CC: aran

Differential Revision: https://secure.phabricator.com/D4878