Author: Julien Boulen
MDL-76317 questions: improve error message when importing invalid grades
http://git.moodle.org/gw?p=moodle.git;a=commit;h=1ed6318d1331d552e89e9e5cbc396adeacdc57ed
http://github.com/moodle/moodle/commit/1ed6318d1331d552e89e9e5cbc396adeacdc57ed
+ 4.4 en [invalidgradequestion,core_question]