+JH/28 Bug 2996: Fix a crash in the smtp transport. When finding that the
+ message being considered for delivery was already being handled by
+ another process, and having an SMTP connection already open, the function
+ to close it tried to use an uninitialized variable. This would afftect
+ high-volume sites more, especially when running mailing-list-style loads.
+ Pollution of logs was the major effect, as the other process delivered
+ the message. Found and partly investigated by Graeme Fowler.
+