CiviEvent 3.4.5 copying an event does not purge permissions cache

Bug is fully described in summary, but specifically this manifests when memcache is in use (with 3.4.5, but I suspect 3.4.8 will be the same).

To reproduce:

1) create an event
2) create a copy of that event
3) be treated to "Sorry. A non-recoverable error has occurred. You do not have permission to access this page."
4) restart memcached
5) reload the edit-new-event page and find it works

Dirty hack patch below which resolves this. Probably requires something more targeted for cache-clearing?

diff --git a/htdocs/sites/all/modules/civicrm/CRM/Event/BAO/Event.php b/htdocs/s
index 0accea4..e57adcc 100644
— a/htdocs/sites/all/modules/civicrm/CRM/Event/BAO/Event.php
+++ b/htdocs/sites/all/modules/civicrm/CRM/Event/BAO/Event.php
@@ -940,6 +940,7 @@ WHERE civicrm_event.is_active = 1
}
}
$copyEvent->save( );
+ CRM_Utils_System::flushCache( );

require_once 'CRM/Utils/Hook.php';
CRM_Utils_Hook::copy( 'Event', $copyEvent );