Notification of string changes

Author: Petr Skoda
MDL-25152 guest logging can be disabled now


http://git.moodle.org/gw?p=moodle.git;a=commit;h=f11f7b41dfc31c213fcb0f6f4b8803c2d0a013a0
http://github.com/moodle/moodle/commit/f11f7b41dfc31c213fcb0f6f4b8803c2d0a013a0

+ 2.0 en [logguests,core_admin]
+ 2.0 en [logguests_help,core_admin]