message: storage: treat cache files as uncompressed when the algorithm is None
  When the compression algorithm is None, treat cache file as uncompressed
  even if user configures it as compressed.
diff: @@ -10,6 +10,7 @@ use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
  use std::sync::{Arc, RwLock};
  use nydus_api::http::{CacheConfig, FileCacheConfig};
  +use nydus_utils::compress;
  use nydus_utils::metrics::BlobcacheMetrics;
  use tokio::runtime::Runtime;
  @@ -188,7 +189,7 @@ impl FileCacheEntry {
  let compressor = blob_info.compressor();
  let digester = blob_info.digester();
  let is_legacy_stargz = blob_info.is_legacy_stargz();
  - let is_compressed = mgr.is_compressed;
  + let is_compressed = mgr.is_compressed && compressor != compress::Algorithm::None;
  let is_zran = blob_info.meta_flags() & BLOB_META_FEATURE_ZRAN != 0;
  let need_validation = (mgr.validate || !is_direct_chunkmap) && !is_legacy_stargz;
  trace!(
  