issue: Delete Org Session Failure

This addresses an issue on the Forum where deleting an Organization causes
the session to fail. This is due to the Organization QuerySet being stored
in the session and not being cleared out when deleted from the system. This
causes the system to try to refetch the object from the database which it's
not there as it's been deleted and therefore causes the session to crash.

include/class.organization.php

@@ -486,6 +486,9 @@ implements TemplateVariable, Searchable {
         if (!parent::delete())
             return false;
 
+        // Clear organization from session to avoid refetch failure
+        unset($_SESSION[':Q:orgs'], $_SESSION[':O:tickets']);
+
         // Remove users from this organization
         User::objects()
             ->filter(array('org' => $this))