Pull Request #611: Increase MAX_REQ_LEN to allow transport of more sophisticated credentials

Hi,

I submitted a pull request 4 weeks ago:

   https://github.com/cyrusimap/cyrus-sasl/pull/611

I just now noticed that the cyrus developer notes say "(a quick note to
the mailing list can speed this along)" regarding getting a review, so
here is my quick note.

-mm