Author: Tomo Tsuyuki
MDL-72451 core: Stop keep regrading when there is an error
Set needsupdate to finish to avoid regrading each call.
Add error messages for regrading.
Display the error message on the quiz page.
Co-authored-by: Mark Johnson <mark.johnson@catalyst-eu.net>
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b3e046df7ee812fb349c407fe78c7f5f849ef116
http://github.com/moodle/moodle/commit/b3e046df7ee812fb349c407fe78c7f5f849ef116
+ 4.2 en [errorcalculationbroken,core_grades]