1 Zone PVAVs getting EMS controls intended for PSZ systems

[mpraprost]

https://github.com/NREL/openstudio-standards/blob/b904ec545cd6fa3959cc41da96014bacb49e7621/lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb#L158-L166

this code adds EMS code to PSZ systems for economizer and staging controls, and it looks for air loops with one thermal zone. this is inadvertently catching 1 zone PVAVs and adding EMS code to these systems when not intended.