Use 'cron_setup_user' when sending emails (#414)

classes/task/email_certificate_task.php

@@ -179,6 +179,9 @@ class email_certificate_task extends \core\task\scheduled_task {
 
             // Now, email the people we need to.
             foreach ($issuedusers as $user) {
+                // Set up the user.
+                cron_setup_user($user);
+
                 $userfullname = fullname($user);
                 $info->userfullname = $userfullname;