Use External inmotion cloud network for zuul nodes

We have limited ipv4 address space in this cloud. Currently we can do
about 6 IP addresses for test nodes after we account for network
infrastructure and the mirror. By switching these instances to using the
external network directly we can clean up some of the neutron network
infrastructure which we think may free up 2 more IP addresses. That
should get us our originally intended max-servers of 8.

Change-Id: I705ff082ff06ae1c97f4c229a22893e6d87d206d

inventory/service/host_vars/bridge.openstack.org.yaml

@@ -361,9 +361,3 @@ cloud_launcher_clouds:
     profiles:
       - openstackci-keypairs
       - openstackci-security
-      - opendevzuul-networking
-    routers:
-      - name: opendevzuul-router1
-        network: External
-        interfaces:
-          - opendevzuul-subnet1

playbooks/templates/clouds/nodepool_clouds.yaml.j2

@@ -161,7 +161,12 @@ clouds:
     image_format: 'raw'
   inmotion:
     regions:
-      - iad3
+      - name: iad3
+        values:
+          networks:
+            - name: External
+              routes_externally: true
+              default_interface: true
     auth:
       auth_url: 'https://173.231.255.228:5000'
       username: '{{ nodepool_inmotion_username }}'