Fix so that if a user sets a per-node lan setting, it can override an interface_setting that was set from the lan itself (i.e., convert an insert to a replace sql stmt).  Necessary so that our wifi docs aren't lying...
Fix so that if a user sets a per-node lan setting, it can override
an interface_setting that was set from the lan itself (i.e., convert an
insert to a replace sql stmt).  Necessary so that our wifi docs
aren't lying...

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