Author: Ankit Agarwal
MDL-58196 availability: Fix UI for pass/fail config
For pass/fail setting to work properly, activities must have 'Require grade' completion set,
just make sure we don't allow activities without this setting to be set
http://git.moodle.org/gw?p=moodle.git;a=commit;h=3e0beaa76bff16c0a109494c3f2fd5a62cf61b7e
http://github.com/moodle/moodle/commit/3e0beaa76bff16c0a109494c3f2fd5a62cf61b7e
+ 3.2 en [error_selectcmidpassfail,availability_completion]