message: utils: no need to impl Default for RafsDigest
diff: @@ -66,7 +66,7 @@ impl DigestHasher for Sha256 {
  }
  }
  -#[derive(Clone, Copy, Hash, PartialEq, Eq, Debug)]
  +#[derive(Clone, Copy, Hash, PartialEq, Eq, Debug, Default)]
  pub struct RafsDigest {
  pub data: DigestData,
  }
  @@ -92,14 +92,6 @@ impl RafsDigest {
  }
  }
  -impl Default for RafsDigest {
  - fn default() -> Self {
  - Self {
  - data: [0u8; RAFS_DIGEST_LENGTH],
  - }
  - }
  -}
  -
  impl From<DigestData> for RafsDigest {
  fn from(data: DigestData) -> Self {
  Self { data }
  