Author: Ashley Holman
MDL-34989 assign: Allow students to submit when grade is overriden
Also inform teachers when grading is disabled due to gradebook lock/override.
Conflicts:
mod/assign/locallib.php
http://git.moodle.org/gw?p=moodle.git;a=commit;h=214dd19aa2bbf6bae07729664738a51ae00e58ec
http://github.com/moodle/moodle/commit/214dd19aa2bbf6bae07729664738a51ae00e58ec
+ 2.4 en [gradelocked,mod_assign]