Remove default_server from nginx.conf

Because when trying to start nginx with oohdir and hines configs in place
we got this error:

```
Dec  2 14:55:49 sylvan systemd[1]: Starting A high performance web server and a reverse proxy server...
Dec  2 14:55:49 sylvan nginx[1653019]: nginx: [emerg] a duplicate default server for 0.0.0.0:80 in /etc/nginx/sites-enabled/oohdir:15
Dec  2 14:55:49 sylvan nginx[1653019]: nginx: configuration file /etc/nginx/nginx.conf test failed
Dec  2 14:55:49 sylvan systemd[1]: nginx.service: Control process exited, code=exited, status=1/FAILURE
Dec  2 14:55:49 sylvan systemd[1]: nginx.service: Failed with result 'exit-code'.
Dec  2 14:55:49 sylvan systemd[1]: Failed to start A high performance web server and a reverse proxy server.
```

For #522

conf/nginx.conf

@@ -11,10 +11,10 @@ upstream hines_app_server {
 
 
 # Return 444 and close connection if no Host header present
-server {
-  listen 80 default_server;
-  return 444;
-}
+# server {
+#   listen 80 default_server;
+#   return 444;
+# }
 
 
 # Redirect http and https gyford.com to https://www.gyford.com