Reset streams should cause an error when the user attempts to read frames about h2

[seanmonstar]

Yes, there is a test for this, added in https://github.com/carllerche/h2/pull/79/files#diff-4f914e238fb524bbb31a2d7da9aa955cR228.

[olix0r]

confirmed that poll_data currently returns None when the underlying connection is lost (i.e. due to a flow control error etc).

in h2::proto::streams::recv

    pub fn poll_data(&mut self, stream: &mut Stream<B, P>)
        -> Poll<Option<Bytes>, proto::Error>
    {
        // TODO: Return error when the stream is reset

[seanmonstar]

I think this was fixed in #79.

[carllerche]

I guess we should confirm then close.