Git commits in Moodle 2.5.1 by Troy Lee

commit 62cf9a1d2a7bb71294227fcccceccccf100e8a34
Author: Troy Lee <troy.lee2008@gmail.com>
Date:   Thu, 09 May 2013 10:13:46 +0800
Tag:    v2.5.1

MDL-36020 overview/report: fix quiz regrade session lock