if the root mount '/' is not mounted as MS_SHARED, print a
warning, otherwise new mounts that are created in the host won't be
propagated to the rootless mount namespace.
Closes: https://github.com/containers/podman/issues/10946
[NO TESTS NEEDED]
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
67d439197e