DIGEST-MD5 authzid question

[Remko Tronçon]

> I would guess that it's to avoid the case where a server
> implementation always rejects any request for an authzid.

Well, I have this problem with an XMPP server, but in XMPP, the
authzid for a user is different from its authid, so the check doesn't
help. Luckily, an authzid in XMPP can never be used as an authid, so
we don't have a problem with the equality check.

cheers,
Remko