[Bug Report] Actionsheet value 为false 还是显示

### VUX version
2.9.2

### OS/Browsers version
Ipad 版本 7.1.2（11D257）/safari

### Vue version
2.5.16

### Code

```html

import {Actionsheet} from 'vux'
export default {
components: {
Actionsheet
},
name: 'ChartHand',
data() {
return {
showSheet: false,
sheetMenus: {
menu1: '放大',
menu2: '缩小',
menu3: '下页',
menu4: '上页'
}
}
}
}

```

### Steps to reproduce
打开页面with actionsheet

### What is Expected?
隐藏状态

### What is actually happening?
显示状态