Staticize dhcp config for eth0

We used to rely on libvirt assigning (and keeping track) of dhcp
leases to configure eth0 ip addresses.
Let's make sure we persist this into os-net-config so that we do
not accidentally lose this config between reboots.

examples/va/hci/edpm-pre-ceph/values.yaml

@@ -45,6 +45,10 @@ data:
           {%- endfor %}
           {% set min_viable_mtu = mtu_list | max %}
           network_config:
+          - type: interface
+            name: nic1
+            use_dhcp: true
+            mtu: {{ min_viable_mtu }}
           - type: ovs_bridge
             name: {{ neutron_physical_bridge_name }}
             mtu: {{ min_viable_mtu }}