Git commits in Moodle 3.1.5 by Brendan Heywood

commit 48f3c5744d3f1591a2fe2412773815be675162f5
Author: Brendan Heywood <brendan@catalyst-au.net>
Date:   Tue, 21 Feb 2017 09:44:59 +0800
Tag:    v3.1.5

MDL-50719 cron: Fixed parallel task lock contention issues


commit b34f0b369f131264ab2b8735ec6e3a0e991d4c1a
Author: Brendan Heywood <brendan@catalyst-au.net>
Date:   Mon, 30 Jan 2017 12:51:50 +0800
Tag:    v3.1.5

MDL-57810 lib: Disable nginx buffers when not required