Author: Shamim Rezaie
MDL-61115 mod_lesson: Lesson overrides to observe group membership
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b392686a65e7a568886ee876215104f502d4d2ab
http://github.com/moodle/moodle/commit/b392686a65e7a568886ee876215104f502d4d2ab
+ 3.8 en [groupsnone,mod_lesson]