Action.refresh no longer works starting on v4.0.0-beta.40

### Version
Any react-native-router-flux version including and higher than 4.0.0-beta.40

### Expected behaviour
`componentWillMount() {
Actions.refresh({onRight: () => this.onButtonPress(), rightTitle: I18n.t("profile.save")})
}`
refreshes the onRight title and action

### Actual behaviour
Instead, it does not do anything when it used to work in previous versions.

### Steps to reproduce
1. Create a project with the latest version
2. Add onRight action in Router component
3. Update the action with the onRefresh event and see that it does not work