Scale up small cover images instead of surrounding them with empty space

Summary: This makes small cover images full-width instead of teeny tiny dots in the middle of an island of whitespace.

Test Plan: Uploaded a small cover image.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D15203

src/applications/files/transform/PhabricatorFileThumbnailTransform.php

@@ -77,6 +77,7 @@ public function generateTransforms() {
       id(new self())
         ->setName(pht('Workcard (526px)'))
         ->setKey(self::TRANSFORM_WORKCARD)
+        ->setScaleUp(true)
         ->setDimensions(526, null),
     );
   }