Restore product from receipt (bug 981235)

Is this parsing querystring-like data? I don't understand what that regex is doing but if it's just splitting on `&` and `=` I'd suggest rewriting this without the regex or using a library. I'd normally do this:

```js
storedata.split('&').forEach(function (pair) {
    var parts = pair.split('=');
    params[parts[0]] = decodeURIComponent(parts[1]);
});
```