Switch to using openstack client for setting the router's gateway

Depends-on: Ifb5a4d1965cd7e75c0c8cf2cfb677e0628b699dc
Change-Id: Iba58f5275cacc7bc82fa2f2d2b96315c2350ab70
diff --git a/lib/neutron_plugins/services/l3 b/lib/neutron_plugins/services/l3
index 569a366..ae086ce 100644
--- a/lib/neutron_plugins/services/l3
+++ b/lib/neutron_plugins/services/l3
@@ -337,7 +337,7 @@
     ext_gw_ip=$(echo $id_and_ext_gw_ip  | get_field 2)
     PUB_SUBNET_ID=$(echo $id_and_ext_gw_ip | get_field 5)
     # Configure the external network as the default router gateway
-    neutron --os-cloud devstack-admin --os-region "$REGION_NAME" router-gateway-set $ROUTER_ID $EXT_NET_ID
+    openstack --os-cloud devstack-admin --os-region "$REGION_NAME" router set --external-gateway $EXT_NET_ID $ROUTER_ID
 
     # This logic is specific to using the l3-agent for layer 3
     if is_service_enabled q-l3 || is_service_enabled neutron-l3;  then
@@ -385,7 +385,7 @@
     # If the external network has not already been set as the default router
     # gateway when configuring an IPv4 public subnet, do so now
     if [[ "$IP_VERSION" == "6" ]]; then
-        neutron --os-cloud devstack-admin --os-region "$REGION_NAME" router-gateway-set $ROUTER_ID $EXT_NET_ID
+        openstack --os-cloud devstack-admin --os-region "$REGION_NAME" set --external-gateway $EXT_NET_ID $ROUTER_ID
     fi
 
     # This logic is specific to using the l3-agent for layer 3