Author: Mathew May
MDL-67144 mod_forum: If no users exist do not show the grading interface
http://git.moodle.org/gw?p=moodle.git;a=commit;h=fc741e030efa7aa571b135680907841744ecbcb8
http://github.com/moodle/moodle/commit/fc741e030efa7aa571b135680907841744ecbcb8
+ 3.8 en [nouserstograde,core_grades]