message: storage: turn free function block_exists into method on Storage
diff: @@ -202,6 +202,14 @@ impl Storage {
  Err(Error::BlockNotFound(hash.clone()))
  }
  + pub fn block_exists(&self, hash: &BlockHash) -> Result<bool> {
  + match self.block_location(hash) {
  + Ok(_) => Ok(true),
  + Err(Error::BlockNotFound(_)) => Ok(false),
  + Err(err) => Err(err),
  + }
  + }
  +
  pub fn read_block_at(
  &self,
  loc: &BlockLocation,
  @@ -311,14 +319,6 @@ pub enum BlockLocation {
  Loose(BlockHash),
  }
  -pub fn block_exists(storage: &Storage, hash: &BlockHash) -> Result<bool> {
  - match storage.block_location(hash) {
  - Ok(_) => Ok(true),
  - Err(Error::BlockNotFound(_)) => Ok(false),
  - Err(err) => Err(err),
  - }
  -}
  -
  enum ReverseSearch {
  Continue,
  Found,
  