Now that we can pass any custom containerd shim to dockerd there is need
for this check. Without this it becomes possible to use wasm shims for
example with images that have "wasi" as the OS.
Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>
(cherry picked from commit 1a3d8019d1)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>