[network][vlan] use ansible fact to populate the template for network

interfaces

as the network interface transition to new names we can still get some
information from the system and use it in our template. This will not
change the name of the interface but it will configure it to our needs.

templates/interfaces.j2

@@ -10,12 +10,12 @@ iface lo inet loopback
 # The primary network interface
 auto br0
 iface br0 inet manual
-        bridge_ports eth0.{{ virtual_machine_vlan }}
+        bridge_ports {{ ansible_default_ipv4.alias }}.{{ virtual_machine_vlan }}
         bridge_fd 1
 
-auto eth0.{{ management_vlan }}
-iface eth0.{{ management_vlan }} inet static
+auto {{ ansible_default_ipv4.alias }}
+iface {{ ansible_default_ipv4.alias }} inet static
 	address {{ ansible_default_ipv4.address }}
         gateway {{ hostvars[ext_gateway]['ansible_host'] }}
         netmask 255.255.255.0
-	vlan-raw-device eth0
+	vlan-raw-device {{ ansible_default_ipv4.alias }}