Changed optimal_score to 0.  This increases the run time slightly (still around a second in most cases) but insures that we use a minimal number of delay nodes.
Changed optimal_score to 0.  This increases the run time slightly (still
around a second in most cases) but insures that we use a minimal number
of delay nodes.

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