MDL-64427 course: Do not allow dirty cm_info during course delete

When deleting a course (especially one containing a large amount of
data) the course mod info cache could contain entries for deleted
activities for a signifcant amount of time making it possible that
users could see errors in Moodle.

lib/moodlelib.php

@@ -5250,6 +5250,7 @@ function remove_course_contents($courseid, $showfeedback = true, array $options
                         // Delete cm and its context - orphaned contexts are purged in cron in case of any race condition.
                         context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
                         $DB->delete_records('course_modules', array('id' => $cm->id));
+                        rebuild_course_cache($cm->course, true);
                     }
                 }
             }
@@ -5286,6 +5287,7 @@ function remove_course_contents($courseid, $showfeedback = true, array $options
         }
         context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
         $DB->delete_records('course_modules', array('id' => $cm->id));
+        rebuild_course_cache($cm->course, true);
     }
 
     if ($showfeedback) {