Merge "Fix sparse image detection"

  if info_dict is None:

    info_dict = LoadInfoDict(input_zip)

  is_sparse = info_dict.get("extfs_sparse_flag")

  if info_dict.get(which + "_disable_sparse"):

    is_sparse = False

  is_sparse = IsSparseImage(os.path.join(tmpdir, "IMAGES", which + ".img"))

  # When target uses 'BOARD_EXT4_SHARE_DUP_BLOCKS := true', images may contain

  # shared blocks (i.e. some blocks will show up in multiple files' block