Author: Marina Glancy
MDL-55333 mod_feedback: work around MySQL tables in join limit
http://git.moodle.org/gw?p=moodle.git;a=commit;h=837fb636d4f41d25870d92b4632388172a4eabbb
http://github.com/moodle/moodle/commit/837fb636d4f41d25870d92b4632388172a4eabbb
+ 3.1 en [questionslimited,mod_feedback]