Git commits in Moodle 2.4.6 by Chris Wharton

commit 5886e039ec9e30a469584209b121ba9d86f9c184
Author: Chris Wharton <chrisw@catalyst.net.nz>
Date:   Thu, 18 Jul 2013 09:44:26 +0800
Tag:    v2.4.6

MDL-40700 cache: Validate memcache key prefix field