{Pairing, Authentication}Status.__getattr__ raises KeyError instead of AttributeError

[trdarr]

We use __getattr__ to make accessing the response data nicer, so __getattr__(self, name) returns self._raw_data[name]. However, if name isn’t in _raw_data, a KeyError will be raised. I think most Python programmers would expect an AttributeError. We should probably also support nested attributes, because auth_request.requester.id is way less pretty than auth_request.requester['id'].