Changed to minimize locking time.  Now locks to extract current view, unlocks , runs assign, lock's again to see if resources are still available, and if not retries.
Changed to minimize locking time.  Now locks to extract current view, unlocks
, runs assign, lock's again to see if resources are still available, and if
not retries.

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