Add indexes by mac to interfaces and iface_counters, and node_id index to the latter as well. Speeds up idlecheck from 10-15 seconds to 1-2 seconds.
Add indexes by mac to interfaces and iface_counters, and node_id index to the latter as well. Speeds up idlecheck from 10-15 seconds to 1-2 seconds.

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