IMP::authenticate() changes

[Chuck Hagenbuch]

I want to MFH the IMP::authenticate() changes since it fixes some errors 
reported to the user, and isn't really a huge change; I'll wait until tomorrow, 
though, in case anyone has objections or problems with the code...

-chuck

--
Charles Hagenbuch, <chuck@horde.org>
"What was and what may be, lie, like children whose faces we cannot see, in the
arms of silence. All we ever have is here, now." - Ursula K. Le Guin