Fix an issue where email is overquoted when attaching objects

Summary:
Currently, if you attach a revision to a task and the revision has a title with quotes or angle brackets in it, they are over-escaped in the email.

Instead, don't do that.

Test Plan: Attached "QUOTES" MATH: 1 < 2 to a task, got a reasonable looking email.

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Differential Revision: https://secure.phabricator.com/D7186