Fix "ManageNetworks" use-case

With change I603521bd00dc100e03c765c25503b5e01f3383e4
the ManageNetworks == False use case was overlooked.

When ManageNetworks is set to False and networks are
not created we need to build network_attrs and
subnet_attrs from the data present in network_data.yaml
and parameters.

Closes-Bug: #1920050
Change-Id: I98a3d582add0d6881cd39433ddb25515f0e0dc31
(cherry picked from commit 80b226c44c)

network/network.j2

@@ -297,13 +297,44 @@ outputs:
               - "{{network.subnets[subnet]['ip_subnet']|default("")}}"
 {%-     endif %}
 {%- endfor %}
+
   network_attrs:
     description: {{network.name}} network's attributes
-    value: {get_attr: [{{network.name}}Network, show]}
+    value:
+      if:
+        - manage_networks
+        - {get_attr: [{{network.name}}Network, show]}
+        - name: {{network.name_lower}}
+          dns_domain:
+            list_join:
+            - '.'
+            - - {{network.name.lower()}}
+              - {get_param: CloudDomain}
+              - ''
+          mtu: {{network.mtu|default('1500')}}
+
   subnet_attrs:
     description: Map of attributes for subnets in the {{network.name}} network
     value:
-      {{network.name_lower}}_subnet: {get_attr: [{{network.name}}Subnet, show]}
+      if:
+        - manage_networks
+        - {{network.name_lower}}_subnet: {get_attr: [{{network.name}}Subnet, show]}
 {%- for subnet in network.subnets|default({}) if network.subnets[subnet].enabled|default(true) %}
           {{subnet}}: {get_attr: [{{network.name}}Subnet_{{subnet}}, show]}
+{%- endfor %}
+        - {{network.name_lower}}_subnet:
+            name: {{network.name_lower}}_subnet
+            cidr: {get_param: {{network.name}}NetCidr}
+            dns_nameservers: []
+            gateway_ip: {get_param: {{network.name}}InterfaceDefaultRoute}
+            host_routes: {get_param: {{network.name}}Routes}
+            ip_version: {if: [is_ipv6, 6, 4]}
+{%- for subnet in network.subnets|default({}) if network.subnets[subnet].enabled|default(true) %}
+          {{subnet}}:
+            name: {{subnet}}
+            cidr: {get_param: {{network.name}}SubnetCidr_{{subnet}}}
+            dns_nameservers: []
+            gateway_ip: {get_param: {{network.name}}InterfaceDefaultRoute_{{subnet}}}
+            host_routes: {get_param: {{network.name}}Routes_{{subnet}}}
+            ip_version: {if: [is_ipv6, 6, 4]}
 {%- endfor %}