Remove support for field names in node_stats url

Field names ended up making the urls too long, fields are still supported as query string parameters though (same as indices stats)

src/main/java/org/elasticsearch/rest/action/admin/cluster/node/stats/RestNodesStatsAction.java

@@ -53,10 +53,8 @@ public class RestNodesStatsAction extends BaseRestHandler {
         controller.registerHandler(GET, "/_nodes/{nodeId}/stats/{metric}", this);
 
         controller.registerHandler(GET, "/_nodes/stats/{metric}/{indexMetric}", this);
-        controller.registerHandler(GET, "/_nodes/stats/{metric}/{indexMetric}/{fields}", this);
 
         controller.registerHandler(GET, "/_nodes/{nodeId}/stats/{metric}/{indexMetric}", this);
-        controller.registerHandler(GET, "/_nodes/{nodeId}/stats/{metric}/{indexMetric}/{fields}", this);
     }
 
     @Override