Author: Sara Arjona
MDL-73233 my: Disable /my page depending on setting
When $CFG->enabledashboard will be disabled, the /my page
will redirect to a different page or display an error message.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=31ed9a6c2fbafcc5754806e0a84d30330ec5ddec
http://github.com/moodle/moodle/commit/31ed9a6c2fbafcc5754806e0a84d30330ec5ddec
+ 4.0 en [error:dashboardisdisabled,core_my]