Initial Let's Encrypt setup for Kosmos subdomains

Refs #6

site-cookbooks/kosmos-wordpress/templates/default/nginx.conf.erb

@@ -1,6 +1,8 @@
 server {
         listen 80;
-        listen <%= @server_port %> ssl;
+        <% if File.exist?(@ssl_cert) && File.exist?(@ssl_key) -%>
+        listen <%= @server_port %> ssl spdy;
+        <% end -%>
         server_name <%= @server_name %> <%= @server_aliases.join(" ") %>;
 
         access_log   /var/log/nginx/<%= @server_name %>.access.log;
@@ -29,6 +31,8 @@ server {
                 fastcgi_param  SCRIPT_FILENAME  <%= @docroot %>$fastcgi_script_name;
         }
 
+        <% if File.exist?(@ssl_cert) && File.exist?(@ssl_key) -%>
         ssl_certificate <%= @ssl_cert %>;
         ssl_certificate_key <%= @ssl_key %>;
+        <% end -%>
 }