Author: Simey Lameze
MDL-64883 mod_chat: convert cron to scheduled task
http://git.moodle.org/gw?p=moodle.git;a=commit;h=958dfd9761deb6091731078e9ddedbec14bd1ebf
http://github.com/moodle/moodle/commit/958dfd9761deb6091731078e9ddedbec14bd1ebf
+ 3.7 en [crontask,mod_chat]