Author: Andrew Nicols
MDL-68169 user: Limit the number of filter conditions
Part of MDL-67743
http://git.moodle.org/gw?p=moodle.git;a=commit;h=110f3ebf54117ab86722ed6d5b5f6d4b53b8ecad
http://github.com/moodle/moodle/commit/110f3ebf54117ab86722ed6d5b5f6d4b53b8ecad
+ 3.9 en [adverbfor_and,core_user]
+ 3.9 en [adverbfor_andnot,core_user]
+ 3.9 en [adverbfor_or,core_user]