#1574 - Update template syntax in nginx module

modules/nginx/templates/site.erb

 <% include_file = lambda do |url| %>
   <% content = Puppet::FileServing::Content.indirection.find(url) %>
   <% if content %>
     <%= content.content %>
   <% else %>
     <% raise StandardError, "Failed to resolve source URL #{url}" %>
   <% end %>
 <% end %>
 
 <% server_name = lambda do |domain, alt_names| %><%= domain %><% @alt_names.each do |name| %>, <%= name %><% end %><% end %>
 
-<% if global_config %>
+<% if @global_config %>
   <%= @global_config %>
 <% end %>
 
 <% if @certificate and @private_key %>
   server
   {
-    server_name <% server_name[domain, alt_names] %>;
+    server_name <% server_name[@domain, @alt_names] %>;
 
-    <% if is_default %>
+    <% if @is_default %>
       listen 80 default_server;
       listen [::]:80 default_server;
     <% else %>
       listen 80;
       listen [::]:80;
     <% end %>
 
     location /
     {
       rewrite (.*) https://$host$1 permanent;
     }
   }
   server
   {
-    server_name <% server_name[domain, alt_names] %>;
+    server_name <% server_name[@domain, @alt_names] %>;
 
-    <% if is_default %>
+    <% if @is_default %>
       listen 443 ssl http2 default_server;
       listen [::]:443 ssl http2 default_server;
     <% else %>
       listen 443 ssl http2;
       listen [::]:443 ssl http2;
     <% end %>
 
-    ssl_certificate <%= certificate %>;
-    ssl_certificate_key <%= private_key %>;
+    ssl_certificate <%= @certificate %>;
+    ssl_certificate_key <%= @private_key %>;
     ssl_dhparam /etc/nginx/dhparam.pem;
 
     add_header Strict-Transport-Security max-age=31536000;
 <% else %>
   server
   {
-    server_name <% server_name[domain, alt_names] %>;
+    server_name <% server_name[@domain, @alt_names] %>;
 
-    <% if is_default %>
+    <% if @is_default %>
       listen 80 default_server;
       listen [::]:80 default_server;
     <% else %>
       listen 80;
       listen [::]:80;
     <% end %>
 <% end %>
 
-access_log /var/log/nginx/<%= log %> <%= log_format %>;
+access_log /var/log/nginx/<%= @log %> <%= @log_format %>;
 
 # redirect server error pages to the static page /50x.html
 #
 error_page 500 502 503 504 /50x.html;
 location = /50x.html
 {
   root /usr/share/nginx/html;
 }
 
 # https://issues.adblockplus.org/ticket/4894
 location /easylistchina+easylist.txt
 {
   if ($http_user_agent = "")
   {
     return 400;
   }
 }
 
 if ($http_host ~ "^(.+)\.$")
 {
   set $canonical_host $1;
   rewrite ^(.*) $scheme://$canonical_host$1 permanent;
 }
 
 <% if @content %>
-  <%= content %>
+  <%= @content %>
 <% end %>
 
 <% if @source %>
-  <% include_file[source] %>
+  <% include_file[@source] %>
 <% end %>
 }