Remove no-longer-necessary hack from QPController.
Remove no-longer-necessary hack from QPController.

Takes out a bit of code that was needed because `collisionDetect` didn't
respect filtering by group for terrain collisions.

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