Git commits in Moodle 3.1.5 by Davo Smith

commit 0e69daef28417f3c1b5f1cedfef567c4f9642c69
Author: Davo Smith <git@davosmith.co.uk>
Date:   Tue, 24 Jan 2017 17:54:32 +0800
Tag:    v3.1.5

MDL-57752 session: fix check_security() session termination