[Dovecot] repeat downloads of message headers in 1.0rc19

[Brian G. Peterson]

I upgraded one server to 1.0rc19 (from rc15) over the weekend, and have 
since received several reports of dovecot erroneously retrieving older 
messages as new mail.  I've seen this myself intermittently on KMail, and 
users have reported it on Thunderbird, Squirrelmail, and Outlook.

I see some things in the archives that suggest that this was a problem in 
older 1.0 release candidates, but hadn't experienced the problem myself 
until just now.

Has anyone else seen this problem?

Regards,

  - Brian