Retry an initial channel produce failure

[jbarlow-mcafee]

Previously, if a call to the channel produce method were to fail due
to the channel token having expired, no attempt was made to
automatically re-authenticate, attempt to obtain a new token, and
repeat the call to the produce method.

With the changes in this commit, an initial failure in a call to the
produce method will be retried, with an attempt made to
re-authenticate and obtain a new token before the second attempt to
perform the produce call. An error is delivered to the produce
callback if consecutive calls fail.