smbd: Remove NT4 compatability handling in posix -> NT ACL conversion

smbd: Remove NT4 compatability handling in posix -> NT ACL conversion

NT4 is long dead, and we should not change which ACL we return based
on what we think the client is.  The reason we should not do this, is
that if we are using vfs_acl_xattr then the hash will break if we do.
Additionally, it would require that the python VFS interface set the
global remote_arch to fake up being a modern client.

This instead seems cleaner and removes untested code (the tests are
updated to then handle the results of the modern codepath).

The supporting 'acl compatability' parameter is also removed.

Andrew Bartlett

Reviewed by: Jeremy Allison <jra@samba.org>
(cherry picked from commit d6c7e9b1ed6f7befbb2239350bba4547ef781e58)