Add a local variable to allow ignoring errors returned via SNMP.
Add a local variable to allow ignoring errors returned via SNMP.

We could plumb this through to a config var, but let's leave it a hack
for now and see if we can find the root cause instead.

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