Git commits in Moodle 2.9.2 by Cameron Ball

commit b2f0dc9d10b5165366e0d6d11b621ae2c5fa87b0
Author: Cameron Ball <cameron@moodle.com>
Date:   Tue, 08 Sep 2015 12:10:07 +0800
Tag:    v2.9.2

MDL-51307 navigation: hide message button