MDL-31405 Assignment: Fixed date in reset to be called for every assignment

mod/assign/locallib.php

@@ -742,7 +742,7 @@ class assign {
             shift_course_mod_dates('assign',
                                     array('duedate', 'allowsubmissionsfromdate', 'cutoffdate'),
                                     $data->timeshift,
-                                    $data->courseid);
+                                    $data->courseid, $this->get_instance()->id);
             $status[] = array('component'=>$componentstr,
                               'item'=>get_string('datechanged'),
                               'error'=>false);