Further hackery to deal with more than 254 physical nodes in the testbed when assigning vnode (control net) IP addresses.  Once we hit 255, we increment the low bit of the network address ala:
Further hackery to deal with more than 254 physical nodes in the testbed
when assigning vnode (control net) IP addresses.  Once we hit 255, we
increment the low bit of the network address ala:

	on pc254: 172.16.254.N
	on pc255: 172.17.1.N

Note that the Utah case is different than the default in that we wrap at
200 rather than 254.  This is so that we "wrap" at the boundary of the
new cluster (which starts at pc201); i.e., pc201 has addresses 172.18.1.N.

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome