/etc/testbed/nodetype uses the CPU speed (gleaned from /var/run/dmesg.boot
by cpuspeed.awk) to distinguish between pc600s and pc850s. The start_if.*
scripts use this to determine whether the node should attempt to dhcp
on this interface.

NOTE: When using the start_if.* scripts, NO interfaces should be set
to DHCP in /etc/rc.conf - this will break things.