Build Lister: order_by default value set to date_scheduled

CLI build lister order defaults to date scheduled.
Example sorting by created_at with an unstartable build. Showing STATUS, CREATED_AT, DATE_SCHEDULED.
Abandoned     2014-10-27 17:21:26   2014-10-27 17:21:31
Abandoned     2014-10-28 04:48:38   2014-10-28 04:48:42
Unstartable     2014-10-29 17:48:12   <NULL>
Abandoned     2014-10-29 17:56:13   2014-10-29 17:56:20
Failed             2014-10-29 18:12:50   2014-10-29 18:12:54
Succeeded     2014-10-30 12:59:14   2014-10-30 12:59:19