fix：clone bug

Author: livehigh

package.json

@@ -1,6 +1,6 @@
 {
   "name": "cos-nodejs-sdk-v5",
-  "version": "2.10.1",
+  "version": "2.10.2",
   "description": "cos nodejs sdk v5",
   "main": "index.js",
   "types": "index.d.ts",

sdk/util.js

@@ -214,7 +214,6 @@ var getFileMd5 = function (readStream, callback) {
 };
 
 function clone(obj) {
-    if (typeof obj !== 'object') return obj;
     return map(obj, function (v) {
         return typeof v === 'object' && v !== null ? clone(v) : v;
     });