Author: Neill Magill
MDL-65443 core: Log when a context is locked or unlocked
http://git.moodle.org/gw?p=moodle.git;a=commit;h=3aa7b0df78f358f97829d74685887876c48e60c7
http://github.com/moodle/moodle/commit/3aa7b0df78f358f97829d74685887876c48e60c7
+ 3.7 en [eventcontextlocked,core_access]
+ 3.7 en [eventcontextunlocked,core_access]