fix param format for dogapi.metric.query

lib/api/metric.js

@@ -130,9 +130,11 @@ function send_all(metrics, callback){
  */
 function query(from, to, query, callback){
     var params = {
-        from: from,
-        to: to,
-        query: query
+        query: {
+            from: from,
+            to: to,
+            query: query
+        }
     };
     client.request("GET", "/query", params, callback);
 }