Author: Mark Nelson
MDL-40908 core_tag: replaced 'update' add_to_log calls with an event
http://git.moodle.org/gw?p=moodle.git;a=commit;h=09fce43469782d40edd4add63e2f7a2ddcc01d27
http://github.com/moodle/moodle/commit/09fce43469782d40edd4add63e2f7a2ddcc01d27
+ 2.7 en [eventtagupdated,core_tag]