Git commits in Moodle 2.5.2 by Tony Levi

commit d4bbe8997f72f03d0ad14a6d45707a812193855b
Author: Tony Levi <tony.levi@netspot.com.au>
Date:   Thu, 06 Jun 2013 12:41:19 +0800
Tag:    v2.5.2

MDL-40035: Avoid rebuild_course_cache always for empty course