fix: non-owned properties cause empty args for mset & hmset (#469)

Author: taichunmin

lib/utils/index.js

@@ -170,13 +170,10 @@ exports.timeout = function (callback, timeout) {
  */
 exports.convertObjectToArray = function (obj) {
   var result = [];
-  var pos = 0;
   for (var key in obj) {
     if (obj.hasOwnProperty(key)) {
-      result[pos] = key;
-      result[pos + 1] = obj[key];
+      result.push(key, obj[key]);
     }
-    pos += 2;
   }
   return result;
 };