Minor fixes for snmpit_remote:
Minor fixes for snmpit_remote:

Add missing argument to RecordVlanInsertion().

Don't return 1 from RemoteDoList() on error.  The caller is expecting a list
and not any sort of error.  Instead, on error we tbdie() which is what other
backend modules do on errors.

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