Author: Stephen Bourget
MDL-54911 mod_feedback: start date should be before the end date
http://git.moodle.org/gw?p=moodle.git;a=commit;h=fdc9faed62d8eb1b1f23a2bdf0b64d3004906b83
http://github.com/moodle/moodle/commit/fdc9faed62d8eb1b1f23a2bdf0b64d3004906b83
+ 3.1 en [closebeforeopen,mod_feedback]