nixos/nginx: serve the status page on localhost servers

The status page is inaccessible by default, unless a virtual host is
added with a `server_name` that's not `localhost`.

This commit moves the status page configuration, so that
it's matched before the main server blocks.

nixos/modules/services/web-servers/nginx/default.nix

@@ -256,8 +256,6 @@ let
 
       ${proxyCachePathConfig}
 
-      ${vhosts}
-
       ${optionalString cfg.statusPage ''
         server {
           listen ${toString cfg.defaultHTTPListenPort};
@@ -275,6 +273,8 @@ let
         }
       ''}
 
+      ${vhosts}
+
       ${cfg.appendHttpConfig}
     }''}