Let _rc_parse_conf stick to parsing /etc/rc.conf and /etc/rc.conf.local

Let _rc_parse_conf stick to parsing /etc/rc.conf and /etc/rc.conf.local
if it's invoked without parameters. It's simpler than adding adding
/etc/rc.conf and /etc/rc.conf.local parameters whereever _rc_parse_conf
is used (e.g. /etc/rc and /etc/netstart).

While here, replace a

        for foo in "$@"; do something; done

by

        for foo; do something; done

ok aja@