Remove dust from page construction

Summary:
  ^\s+(['"])dust\1\s*=>\s*true,?\s*$\n

Test Plan: Looked through the diff.

Reviewers: chad

Reviewed By: chad

CC: aran

Differential Revision: https://secure.phabricator.com/D6769

src/applications/phriction/controller/PhrictionEditController.php

@@ -261,7 +261,6 @@ final class PhrictionEditController
       array(
         'title'   => pht('Edit Document'),
         'device'  => true,
-        'dust'    => true,
       ));
   }