Fix to previous revisions; nodes have roles and interfaces have roles and its good not to use the same variable name for both!
Fix to previous revisions; nodes have roles and interfaces have roles
and its good not to use the same variable name for both!

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