Store review error itself errors out

[Gustavo Niemeyer]

Uploading foo.snap [==========================================================] 100%
Error while processing...|
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/snapcraft/main.py", line 244, in main
    return run(args, project_options)
  File "/usr/lib/python3/dist-packages/snapcraft/main.py", line 288, in run
    _run_store_command(args)
  File "/usr/lib/python3/dist-packages/snapcraft/main.py", line 349, in _run_store_command
    snapcraft.push(args['<snap-file>'], release_channels)
  File "/usr/lib/python3/dist-packages/snapcraft/_store.py", line 457, in push
    result = _push_snap(snap_name, snap_filename)
  File "/usr/lib/python3/dist-packages/snapcraft/_store.py", line 480, in _push_snap
    tracker.raise_for_code()
  File "/usr/lib/python3/dist-packages/snapcraft/storeapi/__init__.py", line 754, in raise_for_code
    raise errors.StoreReviewError(self.__content)
snapcraft.storeapi.errors.StoreReviewError: <exception str() failed>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/snapcraft", line 31, in <module>
    snapcraft.main.main()
  File "/usr/lib/python3/dist-packages/snapcraft/main.py", line 249, in main
    logger.error(str(e))
  File "/usr/lib/python3/dist-packages/snapcraft/internal/errors.py", line 42, in __str__
    return self.fmt.format([], **self.__dict__)
IndexError: tuple index out of range