The logic to ensure at least one compression backend is selected was not updated when lz4, xz and zstd were introduced - Fix that. Signed-off-by: Peter Korsgaard <peter@korsgaard.com> Reviewed-by: Peter Seiderer <ps.report@gmx.net> [Peter: add comment as suggested by Peter Seiderer] Signed-off-by: Peter Korsgaard <peter@korsgaard.com>