Rework to use node_rusage table instead of downloading ganglia data from PLC. node_rusage is updated by rusaged script running on the plab nodes, but that is not installed yet. I'll probably need to tweak these changes once we start getting some data.
Rework to use node_rusage table instead of downloading ganglia data
from PLC. node_rusage is updated by rusaged script running on the plab
nodes, but that is not installed yet. I'll probably need to tweak
these changes once we start getting some data.

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