Merge pull request #343 from qiniu/revert-342-open_objc_sdk_01

adjust release badge

Author: CarlJi

README.md

@@ -5,7 +5,6 @@
 [![Build Status](https://travis-ci.org/qiniu/objc-sdk.svg?branch=master)](https://travis-ci.org/qiniu/objc-sdk)
 [![GitHub release](https://img.shields.io/github/v/tag/qiniu/objc-sdk.svg?label=release)](https://github.com/qiniu/objc-sdk/releases)
 [![codecov](https://codecov.io/gh/qiniu/objc-sdk/branch/master/graph/badge.svg)](https://codecov.io/gh/qiniu/objc-sdk)
-[![Latest Stable Version](http://img.shields.io/cocoapods/v/Qiniu.svg)](https://github.com/qiniu/objc-sdk/releases)
 ![Platform](http://img.shields.io/cocoapods/p/Qiniu.svg)