Author: Tim Hunt
MDL-30559 conditional availability: missing validation of grade rules.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=cc8f03e067d9095a409bb09497cdb22a8bca0894
http://github.com/moodle/moodle/commit/cc8f03e067d9095a409bb09497cdb22a8bca0894
+ 2.1 en [badgradelimits,core_condition]
+ 2.1 en [gradeitembutnolimits,core_condition]
+ 2.1 en [gradelimitsbutnoitem,core_condition]
+ 2.1 en [gradesmustbenumeric,core_condition]