MDL-43454 mod_assignment: Use of undefined constants FILE_*

mod/assignment/type/online/assignment.class.php

@@ -37,6 +37,9 @@ class assignment_online extends assignment_base {
         $editmode = ($editable and $edit);
 
         if ($editmode) {
+            // Loading the constants FILE_INTERNAL and FILE_EXTERNAL.
+            require_once($CFG->dirroot . '/repository/lib.php');
+
             // prepare form and process submitted data
             $editoroptions = array(
                 'noclean'  => false,