<SliderButton /> does not update when 'value' of <Slider /> changed

### Description

`` does not update when 'value' of `` changed

### Reproduce Steps
Run the following code. click the 'Random' button. dev-tool shows 'value' has changed. but slider not moving.
```javascript
import React, { Component } from 'react'
import { Slider } from 'element-react'
import 'element-theme-default/lib/slider.css'

class SliderDemo extends Component {
constructor (props) {
super(props)
this.state = {
value: 0
}
}

render () {
return (

export default SliderDemo

```

### Error Trace (if possible)

none.

### Solution

Expect `` to update when 'value' of `` changed

### Additional Information

The react-dev-tool shows that 'value' of `` did update. but 'value' of inner `` did not. hence UI does not update as expected. everything works well on mount.

Environment:
- OS: macOS 10.13.2 High Sierra
- Node.js: 9.3.0
- react: 16.2.0
- react-dom: 16.2.0
- element-react 1.4.5
- webpack: 3.8.1
- babel-preset-react-app 3.1.0