message: nydus-image: use bail instead of panic
  In order to exit more gracefully.
diff: @@ -449,7 +449,7 @@ impl Node {
  Ok(node_size)
  } else {
  - panic!("dump_bootstrap_v5 should not use v6 inode");
  + bail!("dump_bootstrap_v5 should not use v6 inode");
  }
  }
  