BUG: fix `old_bands` order
BUG: fix `old_bands` order

guillochon/MOSFiT,guillochon/MOSFiT,bmockler/MOSFiT,villrv/MOSFiT,mnicholl/MOSFiT,mnicholl/MOSFiT,villrv/MOSFiT,bmockler/MOSFiT,guillochon/FriendlyFit,mnicholl/MOSFiT,guillochon/MOSFiT