Git commits in Moodle 3.6.2 by Leon Stringer

commit 7ad3a22b791470299e8a453153f099f2bda205ee
Author: Leon Stringer <leon.stringer@ntlworld.com>
Date:   Wed, 12 Dec 2018 01:22:59 +0800
Tag:    v3.6.2

MDL-58596 core_stats: fixed infinite loop cause by DST change