CFT: fix OfflineIMAP lockup in single-threaded mode

[Eygene Ryabinkin]

G'day.

Sun, Jan 27, 2013 at 01:08:12AM +0400, Eygene Ryabinkin wrote:
> I was trying to integrate the fix for the issue #22,
>   https://github.com/OfflineIMAP/offlineimap/issues/22
> but came up with the updated patch,
>   http://codelabs.ru/patches/offlineimap/2012-preliminary-fix-deadlock-singlethreaded-IMAP-sync.diff
> 
> In a nutshell, if you're syncing more than 100 (accounts + messages),
> you will experience a lockup if offlineimap is executed with flag
> "-1".  This patch tries to catch all such problems.  It is not yet in
> the 'next' branch, since I'll be polishing it a bit, but the wider
> testing for it is welcome, both in single-threaded (via "-1") and your
> regular mode of operations.  Comments and reviews are welcome too.

Turned out I had some DKIM-related problems with mail delivery, so
posting this once more (and sorry if people got some 3-4 copies of
this message that was bouncing multiple times).
-- 
rea