Remove incorrect sanity-check from wl_map_insert_at
Remove incorrect sanity-check from wl_map_insert_at

I got a little over-eager with my sanity checks and didn't realize that the
client uses wl_map_insert_at to mark objects as zombies when they come from
the server-side.

Signed-off-by: Jason Ekstrand <68c46a606457643eab92053c1c05574abb26f861@jlekstrand.net>

tulcod/wayland,mchalupa/wayland,eyolfson/wayland,sir-murray/wayland,mchalupa/wayland,sir-murray/wayland,bitfactor/wayland,abooij/wayland,sir-murray/wayland,abooij/wayland,bitfactor/wayland,eyolfson/wayland,mchalupa/wayland,eyolfson/wayland,abooij/wayland,tulcod/wayland,bitfactor/wayland,tulcod/wayland