code: public void deleteKey(String key) throws IOException {
          File keyDir = getKeyDir(key);
          LocalFsBlobStoreFile pf = new LocalFsBlobStoreFile(keyDir, BlobStoreFile.BLOBSTORE_DATA_FILE);
          pf.delete();
          delete(keyDir);
      }
docs: Delete a key from the blob store
  @param key the key to delete
  @throws IOException on any error