Fix typo in CollisionFilterGroup.
Fix typo in CollisionFilterGroup.

Bad copy and paste. testCollisionFilterGroups passes on my machine now.

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