firewall: fix interface renaming

The mdev rules for renaming interfaces at boot seem to not work with
latest Alpine. So rename with ifupdown instead.

roles/firewall/tasks/main.yml

@@ -14,6 +14,14 @@
     insertafter: '^# net devices'
   notify: mkinitfs
 
+- name: Tell ifupdown to also rename network interfaces
+  copy:
+    dest: /etc/network/if-pre-up.d/nameif
+    content: |
+      #!/bin/sh
+      nameif -s
+    mode: 0755
+
 - name: Configure interface names
   template:
     dest: /etc/mactab