Author: Tim Hunt
MDL-31702 quiz: clarify error message that has been confusing people.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=ba3fedfb49f52d5ac31d1607310908a9634d25ae
http://github.com/moodle/moodle/commit/ba3fedfb49f52d5ac31d1607310908a9634d25ae
+ 2.3 en [cannotstartgradesmismatch,mod_quiz]