A bug in the confirm component

There is a bug on the confirm component.

If I bind a variable `false` as v-model to the `Confirm` component, the variable will be initialized `undefined` instead of `false`, so I read the related source code:

in the 'src/components/confirm/index.vue'

```
created () {
this.showValue = this.show
if (this.value) {
this.showValue = this.value
}
},
```

`this.show` is not defined in this file.