--- /datas2/moodles/moodle31+/moodle/lib/classes/plugininfo/mod.php	2017-02-16 09:14:43.000000000 +0100
+++ /datas2/gitworkspace/moodle31/moodle2_version/lib/classes/plugininfo/mod.php	2017-05-03 10:43:09.232885308 +0200
@@ -153,6 +153,7 @@
      */
     public function uninstall_cleanup() {
         global $DB, $CFG;
+        require_once ($CFG->dirroot.'/course/lib.php');
 
         if (!$module = $DB->get_record('modules', array('name' => $this->name))) {
             parent::uninstall_cleanup();
@@ -163,7 +164,7 @@
         if ($coursemods = $DB->get_records('course_modules', array('module' => $module->id))) {
             foreach ($coursemods as $coursemod) {
                 // Do not verify results, there is not much we can do anyway.
-                delete_mod_from_section($coursemod->id, $coursemod->section);
+                \delete_mod_from_section($coursemod->id, $coursemod->section);
             }
         }