[Dovecot] Dovecot 2.0 lock upgrade assertion failure

[Timo Sirainen]

On Sat, 2010-10-09 at 21:25 -0700, Ryan Murray wrote:

> Oct  9 23:02:59 stor29 dovecot: lmtp(4793, user at example.com): Panic:
> file mail-index-lock.c: line 62 (mail_index_lock): assertion failed:
> (index->lock_type == F_UNLCK)

I couldn't reproduce with a quick few tests, but yeah, I see now where I
was thinking wrong when I previously decided to remove this code. I put
it back: http://hg.dovecot.org/dovecot-2.0/rev/ff1ac6f22ba1