Use oscodename grain instead of hard coded trusty

nginx/ng/pkg.sls

     {% if salt['grains.get']('os') == 'Ubuntu' %}
     - ppa: nginx/{{ nginx.ppa_version }}
     {% else %}
-    - name: deb http://ppa.launchpad.net/nginx/{{ nginx.ppa_version }}/ubuntu trusty main
+    - name: deb http://ppa.launchpad.net/nginx/{{ nginx.ppa_version }}/ubuntu {{ grains['oscodename'] }} main
+    #- name: deb http://ppa.launchpad.net/nginx/{{ nginx.ppa_version }}/ubuntu trusty main
     - keyid: C300EE8C
     - keyserver: keyserver.ubuntu.com
     {% endif %}