Author: Simey Lameze
MDL-66360 grade: fix user grade notification sending errors
http://git.moodle.org/gw?p=moodle.git;a=commit;h=175fd687b4830e31ece03a3006668c3105214a49
http://github.com/moodle/moodle/commit/175fd687b4830e31ece03a3006668c3105214a49
+ 3.8 en [gradenotificationmessage,core_grades]