New option -D to daemonize spamd-setup for early bootup use. This avoids
spamd-setup hanging if there are various (network?) issues and the system
not proceeding to multiuser so that this can be debugged. We do not use
& for startup in /etc/rc because this makes the spamd-setup a child of the
rc scripts after bootup (that is gross)
Problem reported in PR 5864, change discussed with beck, ok millert