This is what I *should* have done back then; thanks to Jeff Mitchell for
pointing out a problem with the old method.
The old one is *definitely* a kludge. <shamefaced grin>
The log message format has changed. All log messages now have a common
prefix (timestamp, user, IP). This is followed by $SSH_ORIGINAL_COMMAND
(or, in one special case, the name of the user's login shell). Any
further text appears after this (currently this only happens in the case
of a successful push -- one for each ref pushed successfully)