Fix a bug that allowed users with the Administrator role to bypass custom permissions for the "Appearance -> Customize" menu item by going directly to the page URL, "/wp-admin/customize.php".

This bug did not affect other menu items, only "Customize". 

git-svn-id: https://plugins.svn.wordpress.org/admin-menu-editor/trunk@1018752 b8457f37-d9ea-0310-8a92-e5e31aec5664