Enforce PPA's on Ubuntu(s) only; not Debian

nginx/ng/pkg.sls

@@ -51,6 +51,8 @@ nginx_official_repo:
     - watch_in:
       - pkg: nginx_install
 
+   {%- if grains.os not in ('Debian',) %}
+       ## applies to Ubuntu and derivatives only #}
 nginx_ppa_repo:
   pkgrepo:
     {%- if from_ppa %}
@@ -69,6 +71,7 @@ nginx_ppa_repo:
       - pkg: nginx_install
     - watch_in:
       - pkg: nginx_install
+   {%- endif %}
 
 nginx_phusionpassenger_repo:
   pkgrepo: