Checkbox is not checked when binded value is 1

### Vue.js version
2.1.7

### Reproduction Link
[Codepen](http://codepen.io/Aterbonus/pen/MbMVKj)

### Steps to reproduce
Input of type checkbox binded with value equals to 1.
 
### What is Expected?
The input has to be checked.

### What is actually happening?
The input is not checked. In versions 2.1.6 and below is working as expected.