Allow TCP/UDP services in /etc/rc.firewall

Small patch that changes workstation profile in /etc/rc.firewall to
allow UDP services.  All ports without a protocol specifier are
treated as TCP by default to keep backwards compatibility.

For example, setting

firewall_myservices="22 tcp:2000 udp:2001"

in /etc/rc.conf creates ipfw rules for tcp ports 22,2000 and udp port 2001.

-j