Author: Adrian Greeve
MDL-49380 enrol_cohort: Update to code and introduction of a constant.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=7efd0c0adbfaa0ff1826e827f71b88a8fe484bde
http://github.com/moodle/moodle/commit/7efd0c0adbfaa0ff1826e827f71b88a8fe484bde
+ 2.9 en [defaultgroupnametext,enrol_cohort]