Author: Shamim Rezaie
MDL-65399 mod_quiz: UI should prevent deleting the last slot of section
http://git.moodle.org/gw?p=moodle.git;a=commit;h=fe3d98f0a082a7c8afa3e5ca64c60078e07dc0ce
http://github.com/moodle/moodle/commit/fe3d98f0a082a7c8afa3e5ca64c60078e07dc0ce
+ 3.6 en [cannotremoveallsectionslots,mod_quiz]
+ 3.6 en [cannotremoveslots,mod_quiz]