customize upload button children by user

components/upload/demo/basic.md

@@ -24,7 +24,9 @@ var props = {
 };
 
 React.render(
-  <Upload {...props} />,
+  <Upload {...props}>
+    <i className="anticon anticon-upload"></i> 点击上传
+  </Upload>,
   document.getElementById('components-upload-demo-basic')
 );
 ````

components/upload/index.jsx

@@ -97,7 +97,7 @@ let AntUpload = React.createClass({
         <div className={prefixCls + ' ' + prefixCls + '-select'}>
           <Upload {...props}>
             <button className='ant-btn ant-btn-ghost'>
-              <i className='anticon anticon-upload'></i> 点击上传
+              {this.props.children}
             </button>
           </Upload>
           <UploadList items={this.state.downloadList} />