Update README.md

The file in sample is named nginx.conf, not kibana.conf.

README.md

@@ -42,7 +42,7 @@ config.js setup works for the webserver+Elasticsearch on the same machine scenar
 to http://localhost:9200 unless your browser Wnd elasticsearch are on the same machine
 
 __Q__: How do I secure this? I don't want to leave 9200 open.  
-__A__: A simple nginx virtual host and proxy configuration can be found in the sample/kibana.conf 
+__A__: A simple nginx virtual host and proxy configuration can be found in the sample/nginx.conf 
 
 ### Support