message: storage: fix typo in a unit test case
  Fix typo in a unit test case, we should test the inode data read from
  disk.
diff: @@ -1919,10 +1919,10 @@ pub mod tests {
  inode2.load(&mut reader).unwrap();
  assert_eq!(inode2.i_name_size, 4);
  assert_eq!(inode2.i_symlink_size, 6);
  - assert_eq!(inode.i_size, 0x1000);
  - assert_eq!(inode.i_blocks, 1);
  - assert_eq!(inode.i_child_count, 10);
  - assert_eq!(inode.i_child_index, 20);
  + assert_eq!(inode2.i_size, 0x1000);
  + assert_eq!(inode2.i_blocks, 1);
  + assert_eq!(inode2.i_child_count, 10);
  + assert_eq!(inode2.i_child_index, 20);
  let filename = inode2.load_file_name(&mut reader).unwrap();
  assert_eq!(filename, OsString::from_str("test").unwrap());
  