Use white for active state on mobile menus

Summary: Perviously we used {$sky} but we've since change the icons to .8 opacity on white, allowing use of white on select.

Test Plan: Click on the mobile menu, see icon turn white instead of blue.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12430

src/view/page/menu/PhabricatorMainMenuView.php

@@ -144,7 +144,7 @@ final class PhabricatorMainMenuView extends AphrontView {
         'meta'  => array(
           'map' => array(
             $header_id => 'phabricator-application-menu-expanded',
-            $button_id => 'sky',
+            $button_id => 'white',
           ),
         ),
       ),
@@ -207,7 +207,7 @@ final class PhabricatorMainMenuView extends AphrontView {
         'meta'  => array(
           'map' => array(
             $header_id => 'phabricator-search-menu-expanded',
-            $button_id => 'sky',
+            $button_id => 'white',
           ),
         ),
       ),