Fixing whitelist validation

Change-Id: I4fc38a67e5294d30ff3d9cf2d98bef68eaa4f1d0
diff --git a/xos/synchronizer/steps/sync_att_workflow_driver_service_instance.py b/xos/synchronizer/steps/sync_att_workflow_driver_service_instance.py
index 1726e50..0b9546b 100644
--- a/xos/synchronizer/steps/sync_att_workflow_driver_service_instance.py
+++ b/xos/synchronizer/steps/sync_att_workflow_driver_service_instance.py
@@ -40,7 +40,7 @@
             return False
 
         whitelisted = matching_entries[0]
-        pon_port = ONUDevice.objects.get().pon_port
+        pon_port = ONUDevice.objects.get(serial_number=si.serial_number).pon_port
         if pon_port.port_no != whitelisted.pon_port_id or si.of_dpid != whitelisted.device_id:
             log.warn("ONU disable as location don't match", object=str(si), serial_number=si.serial_number,
                      **si.tologdict())