Squashed commit of the following:

commit 74c5e4cce42ae601c07b447e100f097c15ebf9d2
Author: Evan Prodromou <evan@status.net>
Date:   Thu Oct 20 12:48:52 2011 -0400

    Add back in some optimization indices lost in schema conversion

commit ef5c2acfcd123b25910a1c8bb4ae01a3f9608e5e
Author: Evan Prodromou <evan@status.net>
Date:   Thu Oct 20 12:29:57 2011 -0400

    restore some of the lost optimized indices on notice table

classes/Group_inbox.php

@@ -37,6 +37,7 @@ class Group_inbox extends Managed_DataObject
             'indexes' => array(
                 'group_inbox_created_idx' => array('created'),
                 'group_inbox_notice_id_idx' => array('notice_id'),
+                'group_inbox_group_id_created_notice_id_idx' => array('group_id', 'created', 'notice_id'),
             ),
         );
     }