load_dataset('cnn_dalymail', '3.0.0') gives a 'Not a directory' error 
 ```
from datasets import load_dataset
dataset = load_dataset('cnn_dailymail', '3.0.0')
```
Stack trace:
```
---------------------------------------------------------------------------

NotADirectoryError                        Traceback (most recent call last)

<ipython-input-6-2e06a8332652> in <module>()
      1 from datasets import load_dataset
----> 2 dataset = load_dataset('cnn_dailymail', '3.0.0')

5 frames

/usr/local/lib/python3.6/dist-packages/datasets/load.py in load_dataset(path, name, data_dir, data_files, split, cache_dir, features, download_config, download_mode, ignore_verifications, save_infos, script_version, **config_kwargs)
    608         download_config=download_config,
    609         download_mode=download_mode,
--> 610         ignore_verifications=ignore_verifications,
    611     )
    612 

/usr/local/lib/python3.6/dist-packages/datasets/builder.py in download_and_prepare(self, download_config, download_mode, ignore_verifications, try_from_hf_gcs, dl_manager, **download_and_prepare_kwargs)
    513                     if not downloaded_from_gcs:
    514                         self._download_and_prepare(
--> 515                             dl_manager=dl_manager, verify_infos=verify_infos, **download_and_prepare_kwargs
    516                         )
    517                     # Sync info

/usr/local/lib/python3.6/dist-packages/datasets/builder.py in _download_and_prepare(self, dl_manager, verify_infos, **prepare_split_kwargs)
    568         split_dict = SplitDict(dataset_name=self.name)
    569         split_generators_kwargs = self._make_split_generators_kwargs(prepare_split_kwargs)
--> 570         split_generators = self._split_generators(dl_manager, **split_generators_kwargs)
    571 
    572         # Checksums verification

/root/.cache/huggingface/modules/datasets_modules/datasets/cnn_dailymail/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602/cnn_dailymail.py in _split_generators(self, dl_manager)
    252     def _split_generators(self, dl_manager):
    253         dl_paths = dl_manager.download_and_extract(_DL_URLS)
--> 254         train_files = _subset_filenames(dl_paths, datasets.Split.TRAIN)
    255         # Generate shared vocabulary
    256 

/root/.cache/huggingface/modules/datasets_modules/datasets/cnn_dailymail/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602/cnn_dailymail.py in _subset_filenames(dl_paths, split)
    153     else:
    154         logging.fatal("Unsupported split: %s", split)
--> 155     cnn = _find_files(dl_paths, "cnn", urls)
    156     dm = _find_files(dl_paths, "dm", urls)
    157     return cnn + dm

/root/.cache/huggingface/modules/datasets_modules/datasets/cnn_dailymail/0128610a44e10f25b4af6689441c72af86205282d26399642f7db38fa7535602/cnn_dailymail.py in _find_files(dl_paths, publisher, url_dict)
    132     else:
    133         logging.fatal("Unsupported publisher: %s", publisher)
--> 134     files = sorted(os.listdir(top_dir))
    135 
    136     ret_files = []

NotADirectoryError: [Errno 20] Not a directory: '/root/.cache/huggingface/datasets/downloads/1bc05d24fa6dda2468e83a73cf6dc207226e01e3c48a507ea716dc0421da583b/cnn/stories'
```
I have ran the code on Google Colab 
 > atal("Unsupported publisher: %s", publisher) --> 134 files = sorted(os.listdir(top_dir)) 135 136 ret_files = []
> 
> NotADirectoryError: [Errno 20] Not a directory: '/root/.cache/huggingface/datasets/downloads/1bc05d24fa6dda2468e83a73cf6dc207226e01e3c48a507ea716dc0421da583b/cnn/stories'
> 
> Can someone please take a look ?

2 short-term workarounds:

1.  Use this line instead `dataset = load_dataset('ccdv/cnn_dailymail', '3.0.0')`. [In a related issue](https://github.com/huggingface/datasets/issues/996#issuecomment-997343101), this person mentioned another data source copy that just works.
2.  Use the same data source, but edit the urls.  Instead of google drive quota problems mentioned in #996, I was getting the "can't scan this file for viruses" problem, which results in that prompted html getting downloaded instead of the files.  You can get around this by:
    1. Look at the traceback and find out where `cnn_dailymail.py` is on your computer.
    2. Edit the `cnn_stories` and `dm_stories` url's by adding the following to the end of them `&confirm=t`.  This should be around line 67.
    3. You may have to remove those confirmation html files in your download directory (`~/.cache/huggingface/datasets/downloads` for me) so that they don't get in the way of the new download attempts.

Either method works for me.  I would've made a PR, but not sure if they want to go with the new ccdv/cnn_dailymail source or not.