Fix server info query for firewalls
Fix server info query for firewalls

Fixed the query for server name, ip, and mac so that it works with
multiple subbosses.  Previously the query would fail due to the
subquery returning multiple rows.

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