Add a "failstop" command line argument for frisbee MFS.
Add a "failstop" command line argument for frisbee MFS.

If specified on the kernel command line in the pxelinux.cfg config,
the init script will drop to a shell prompt when frisbee fails.
With failstop off, it will instead report via "tmcc bootlog", wait
a couple of seconds, and then reboot in order to try again.

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