There is no functional change but it seems better to get size by calling
posix_acl_xattr_size() instead of calling posix_acl_to_xattr() with
NULL buffer argument. Additionally, remove unnecessary assignments.
Signed-off-by: NChengguang Xu <cgxu519@gmx.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>