Git commits in Moodle 2.6.x by Troy Lee

commit 62af3fe42bd256aba01376fdebb3fad290312a8d
Author: Troy Lee <troy.lee2008@gmail.com>
Date:   Thu, 09 May 2013 10:13:46 +0800
Tag:    v2.6.0-beta

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