Adding Custom Changes for Debian

Adding a require to /etc/apt/listchanges.conf for the package
apt-listchanges so that listchanges.conf doesn't get added before the
listchanges package is installed causing apt to hit a catch 22.

Add an if statement to 50unattended-upgrades so that Debian doesn't
get Unattended-Upgrade::Allowed-Origins which doesn't work and causes
unattended upgrades to stop.

apt/listchanges.sls

     - group: root
     - mode: 644
     - source: {{ listchanges_config_template }}
+    - require:
+      - pkg: apt-listchanges

apt/templates/unattended_config.jinja

 {% set automatic_reboot = unattended.get('automatic_reboot', 'false') -%}
 {% set automatic_reboot_time = unattended.get('automatic_reboot_time', 'now') -%}
 {% set dl_limit = unattended.get('dl_limit', '0') -%}
+{%- if salt['grains.get']('os') != 'Debian' -%}
 Unattended-Upgrade::Allowed-Origins {
         {%- for pattern in allowed_origins %}
         "{{ pattern }}";
         {%- endfor %}
 };
+{%- endif %}
 Unattended-Upgrade::Origins-Pattern {
         {%- for pattern in origins_patterns %}
         "{{ pattern }}";