case that the mysql server goes away suddenly. Defaults to 1, which
gives us the behaviour we have now. Used like this after loading libdb:

	$libdb::DBQUERY_MAXTRIES = 5;

The query will be retried this many times. For infinite retry, set it
to zero! Note that I'm not entirely sure if queries are atomic, so
beware if you use this.

Also some minor cleanup of $scriptname usage, some of which was
duplicated in the connect routine.