OSU OSL : add default network

The public5 network has the most IP addresses available and is
recommended for use.

This cloud also has fixed public IP's, not floating

Change-Id: I7ae1bb0081d3a86149225c3400b53a9561ccffe6

playbooks/templates/clouds/nodepool_clouds.yaml.j2

@@ -144,7 +144,11 @@ clouds:
       user_domain_name: CCP_Domain_34466
   osuosl:
     regions:
-      - RegionOne
+      - name: RegionOne
+        values:
+          networks:
+            - name: public5
+              default_interface: True
     auth:
       auth_url: https://arm-openstack.osuosl.org:5000/v3
       username: '{{ nodepool_osuosl_username }}'
@@ -152,4 +156,5 @@ clouds:
       project_name: 'opendevzuul'
       project_id: '{{ nodepool_osuosl_project_id }}'
       user_domain_name: "Default"
+    floating_ip_source: None
     identity_api_version: 3