[Dovecot] warnings from 2.0.11

[Mike Abbott]

> What kind of a test are you doing that causes these warnings?

A stress test which manipulates messages via IMAP fetch, copy, search, append, store flags, expunge, etc. and also sends mail via SMTP.  I'll try to narrow down if there's a specific command which triggers it, or if dovecot-lda does, or what.  Meanwhile I would welcome your educated guesses as to where to look.