Prevent `reconnect timeout` from defaulting to `NaN`

The reason for this change is that https://github.com/unshiftio/recovery/blob/e4c6d529f54f463256e63c14246cbad02ee56d6d/index.js#L46 will default to `NaN` because we don't have a `reconnect timeout` property on the `Recovery` class.
So we either rename everything, including the `attempt` properties or revert the original change.