fix building without bullet; collision/test/CMakeLists wasn't checking for it properly
fix building without bullet; collision/test/CMakeLists wasn't checking for it properly

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