adding serial_number to the OLT

Change-Id: I41abd95dc0b0c0f7c6e46ee2fe24836b73ec8d36
diff --git a/tosca-configs/att-workflow/onlab-pod1-qa-olt.yaml b/tosca-configs/att-workflow/onlab-pod1-qa-olt.yaml
index f666eac..dff53e4 100755
--- a/tosca-configs/att-workflow/onlab-pod1-qa-olt.yaml
+++ b/tosca-configs/att-workflow/onlab-pod1-qa-olt.yaml
@@ -39,6 +39,7 @@
         port: 9191
         switch_datapath_id: of:0000000000000001
         switch_port: "1"
+        serial_number: "EC1721000208"
         outer_tpid: "0x8100"
         uplink: "65536"
         nas_id: "NAS_ID"