Author: Mark Nelson
MDL-40063 mod_quiz: replaced 'preview' add_to_log call with an event
http://git.moodle.org/gw?p=moodle.git;a=commit;h=45e1e3bd76e50b068a550a1a4315d9d262ff22f4
http://github.com/moodle/moodle/commit/45e1e3bd76e50b068a550a1a4315d9d262ff22f4
+ 2.7 en [eventattemptpreviewstarted,mod_quiz]