[horde] unserialize error in HEAD

[Derek J. Balling]

I've started seeing

Notice: unserialize() failed at offset 0 of 36 bytes in 
/usr/local/hordecvs/horde/lib/Auth.php on line 299

and apparently it's happening early enough that it is often followed by 
things like:

Warning: Cannot add header information - headers already sent by 
(output started at /usr/local/hordecvs/horde/lib/Auth.php:299) in 
/usr/local/hordecvs/horde/imp/login.php on line 77

:(  I'm now totally stuck. (yes, that's what I get for running HEAD in 
production, but my bosses are chomping at the bit for shared calendars)

D