Fix copy/paste error which prevented correct functionality.
Network Preflet: EthernetSettingsView::_BuildInterfacesMenu()
needs to call SetTargetForItems(), otherwise selecting interfaces
in the popup menu doesn't work.
Network Preflet: Call _SetConfiguration(NULL) in _BuildInterfacesMenu()
if no interface is present, thus effectively disabling the other
controls. Also if there is only one interface, select that one.