httpAddress -> http_address, closes elastic#118.

Author: kimchy

modules/elasticsearch/src/main/java/org/elasticsearch/http/HttpServer.java

@@ -86,11 +86,11 @@ public void registerHandler(HttpRequest.Method method, String path, HttpServerHa
         if (logger.isInfoEnabled()) {
             logger.info("{}", transport.boundAddress());
         }
-        nodesInfo.putNodeAttribute("httpAddress", transport.boundAddress().publishAddress().toString());
+        nodesInfo.putNodeAttribute("http_address", transport.boundAddress().publishAddress().toString());
     }
 
     @Override protected void doStop() throws ElasticSearchException {
-        nodesInfo.removeNodeAttribute("httpAddress");
+        nodesInfo.removeNodeAttribute("http_address");
         transport.stop();
     }