message: nydus-image: fix diff builder to generate blob meta info
diff: @@ -230,6 +230,8 @@ fn dump_blob(
  ) -> Result<BlobContext> {
  let mut blob_ctx = BlobContext::new(blob_id, blob_storage)?;
  blob_ctx.set_chunk_dict(chunk_dict);
  + blob_ctx.set_chunk_size(ctx.chunk_size);
  + blob_ctx.set_meta_info_enabled(true);
  // Since all layers are built concurrently, it is not possible to deduplicate
  // chunk between layers while ensuring reproducible build, so we only do
  