Fix two minor Differential issues

Summary:
  - D6966 accidentally reversed the order of `$diffs`. Reverse it back.
  - The new policy header stuff returns `array(icon, text)` but gets `strlen()`'d by a caller. Silence that warning for now.

Test Plan: Created a revision with several diffs. Saw them in the right order; saw no warning on the diff attach screen.

Reviewers: chad, btrahan

Reviewed By: chad

CC: aran, mbishopim3

Differential Revision: https://secure.phabricator.com/D7023

src/applications/differential/controller/DifferentialRevisionViewController.php

@@ -33,6 +33,7 @@ final class DifferentialRevisionViewController extends DifferentialController {
       ->setViewer($request->getUser())
       ->withRevisionIDs(array($this->revisionID))
       ->execute();
+    $diffs = array_reverse($diffs);
 
     if (!$diffs) {
       throw new Exception(

src/applications/differential/field/specification/DifferentialDiffViewPolicyFieldSpecification.php

@@ -19,7 +19,9 @@ final class DifferentialDiffViewPolicyFieldSpecification
       $user,
       $diff);
 
-    return idx($descriptions, PhabricatorPolicyCapability::CAN_VIEW);
+    // TODO: Clean this up with new policy UI.
+    $policy = idx($descriptions, PhabricatorPolicyCapability::CAN_VIEW);
+    return $policy[1];
   }
 
 }