fix typo

booking.variety_admin.inc

@@ -411,7 +411,7 @@ function booking_varietysessions_csv_report($timeslot_id) {
   //get the list of study group session memberships
   $session_members_query = db_query("SELECT r.*, p.* FROM {booking_variety_regn} r
     inner join {booking_person} p on p.nid = r.booking_person_nid
-    WHERE p.booking_eventid = :eid ORDER BY r.brid", 
+    WHERE p.booking_eventid = :eid ORDER BY r.rid", 
     array(':eid' => $event->eid));
   $session_members = $session_members_query->fetchAll();