R1:e4736bf9778b

Avoid double escaping in error view title

Summary: Searched for `AphrontErrorView` and then for `setTitle()`.

Test Plan: None.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4880