修复 输入框 clear 失效的bug review by daiqiang

@@ -118,7 +118,16 @@ export default class Detail extends Component {
             relayToUsername = '';
         }
         this.props.onSubmitForComment && this.props.onSubmitForComment(content,replyTos);
+
         this.refs.textInput.clear();
+
+        if (Platform.OS === 'ios') {
+        	this.refs.textInput.setNativeProps({ text: ' ' });
+          setTimeout(() => {
+            this.refs.textInput.setNativeProps({ text: '' });
+          });
+        }
+
         this.setState({replyTo: 0,relayToUsername: ''});
     }