Merge pull request #275 from anderbubble/issues/274

Ignore missing servers or snippets when removing from map

nginx/certificates.sls

     - creates: {{ certificates_path }}/{{ dh_param }}
     - require:
       - file: prepare_certificates_path_dir
+      - pkg: generate_nginx_dhparam_{{ dh_param }}_key
     - watch_in:
       - service: nginx_service
 {%- endif %}

nginx/servers_config.sls

 {% set server_states = [] %}
 {#- _nginx is a lightened copy of nginx map intended to passed in templates #}
 {%- set _nginx = nginx.copy() %}
-{%- do _nginx.pop('snippets') %}
-{%- do _nginx.pop('servers') %}
+{%- do _nginx.pop('snippets') if nginx.snippets is defined %}
+{%- do _nginx.pop('servers') if nginx.servers is defined %}
 
 # Simple path concatenation.
 # Needs work to make this function on windows.

nginx/snippets.sls

 
 {#- _nginx is a lightened copy of nginx map intended to passed in templates #}
 {%- set _nginx = nginx.copy() %}
-{%- do _nginx.pop('snippets') %}
-{%- do _nginx.pop('servers') %}
+{%- do _nginx.pop('snippets') if nginx.snippets is defined %}
+{%- do _nginx.pop('servers') if nginx.servers is defined %}
 
 nginx_snippets_dir:
   file.directory: