Git commits in Moodle 3.1.18 by Dan Marsden

commit a6258d0934f707b1d033f50fb41ffbcf45bb2102
Author: Dan Marsden <dan@danmarsden.com>
Date:   Wed, 01 May 2019 09:23:15 +0800
Tag:    v3.1.18

MDL-64708 cohort: Return url is not used anywhere in core.