Bug#289458: callout verification and synchronization checks bite each other

[Florian Weimer]

* Andreas Barth:

> On my system, errors like this are logged:
> 2005-01-09 09:27:12 SMTP protocol violation: synchronization error (input sent without waiting for greeting): rejected connection from H=costa.debian.org [217.196.43.131]

FYI: Philip Hazel has updated the Exim 4.50 snapshot to include a more
informative message.  The callout code has also been fixed, and the
synchronization error no longer occurs.