Fix erroneous property in RigidBodyFlatTerrain
Fix erroneous property in RigidBodyFlatTerrain

crogers3/drake,crogers3/drake,astrorog/drake,billhoffman/drake,hanssusilo/drake,edowson/drake,scottviteri/drake,manuelli/drake,thientu/drake,sheim/drake,scottviteri/drake,scottviteri/drake,astrorog/drake,sheim/drake,hanssusilo/drake,billhoffman/drake,crogers3/drake,psiorx/drake,sheim/drake,scottviteri/drake,scottviteri/drake,psiorx/drake,manuelli/drake,astrorog/drake,thientu/drake,hanssusilo/drake,psiorx/drake,billhoffman/drake,manuelli/drake,sheim/drake,billhoffman/drake,thientu/drake,hanssusilo/drake,hanssusilo/drake,psiorx/drake,edowson/drake,tkoolen/drake,crogers3/drake,edowson/drake,sheim/drake,edowson/drake,tkoolen/drake,crogers3/drake,edowson/drake,crogers3/drake,psiorx/drake,manuelli/drake,manuelli/drake,thientu/drake,edowson/drake,billhoffman/drake,psiorx/drake,scottviteri/drake,tkoolen/drake,astrorog/drake,billhoffman/drake,astrorog/drake,tkoolen/drake,hanssusilo/drake,edowson/drake,hanssusilo/drake,crogers3/drake,billhoffman/drake,psiorx/drake,crogers3/drake,edowson/drake,billhoffman/drake,thientu/drake,scottviteri/drake,thientu/drake,sheim/drake,manuelli/drake,sheim/drake,psiorx/drake,tkoolen/drake,hanssusilo/drake,manuelli/drake,tkoolen/drake,tkoolen/drake,sheim/drake,astrorog/drake,astrorog/drake,thientu/drake