Author: Alec Gullon
MDL-79464 mod_assign: Limit user navigation if grading fails validation
http://git.moodle.org/gw?p=moodle.git;a=commit;h=c7d7c5a8c8ec3db24bf870d000482555ec42e881
http://github.com/moodle/moodle/commit/c7d7c5a8c8ec3db24bf870d000482555ec42e881
+ 4.4 en [errorgradechangessaveddetail,mod_assign]