Author: Michael Wheeler
MDL-46960 completionlib: Move completion cache to MUC.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=3871db0ac23e05fb42641ed779e506bbe8444072
http://github.com/moodle/moodle/commit/3871db0ac23e05fb42641ed779e506bbe8444072
+ 2.9 en [cachedef_completion,core_cache]