Author: rajandangi
MDL-79628 navigation: Refactor navigation_cache to use MUC
http://git.moodle.org/gw?p=moodle.git;a=commit;h=16194847162db8ecd41d864a22d763a793acc939
http://github.com/moodle/moodle/commit/16194847162db8ecd41d864a22d763a793acc939
+ 4.3 en [cachedef_navigation_cache,core_cache]