roles/common: Use iptables 1.8.3 on Debian Buster

There is a bug in iptables 1.8.2 in Debian 10 "Buster" that causes
firewalld to fail when restoring rules. The bug has been fixed in
iptables 1.8.3, which is currently in buster-backports.

See: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=914694

roles/common/tasks/firewall_Debian.yml

@@ -1,6 +1,10 @@
 ---
 
 - block:
+  - name: Install iptables 1.8.3 on Debian Buster
+    when: ansible_distribution_major_version is version_compare('10', '==')
+    apt: pkg=iptables state=present default_release=buster-backports
+
   - name: Install firewalld and deps
     when: ansible_distribution_major_version is version_compare('8', '>=')
     apt: pkg={{ item }} state=present

roles/common/templates/sources.list.j2

@@ -12,4 +12,9 @@ deb http://{{ apt_mirror }}/debian/ {{ ansible_distribution_release }} main cont
 deb http://security.debian.org/debian-security {{ ansible_distribution_release }}/updates main contrib non-free
 
 deb http://{{ apt_mirror }}/debian/ {{ ansible_distribution_release }}-updates main contrib non-free
+
+{% if ansible_distribution_major_version is version_compare('10', '==') %}
+deb http://{{ apt_mirror }}/debian/ buster-backports main
+{% endif %}
+
 {% endif %} {# ansible_distribution #}