Comment 0 for bug 1979637

Run following shell script:

```sh
echo "raise ValueError()" > /tmp/failure.py
mkdir /tmp/foo
cd /tmp/foo/
rmdir /tmp/foo/
python3 ../failure.py
```

Python should only show a ValueError, but apport_python_hook.py crashes:

```
Traceback (most recent call last):
  File "../failure.py", line 1, in <module>
    raise ValueError()
ValueError
Error in sys.excepthook:
Traceback (most recent call last):
  File "<frozen importlib._bootstrap_external>", line 1372, in _path_importer_cache
KeyError: '..'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 55, in apport_excepthook
    import apt_pkg
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1002, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 945, in _find_spec
  File "<frozen importlib._bootstrap_external>", line 1439, in find_spec
  File "<frozen importlib._bootstrap_external>", line 1408, in _get_spec
  File "<frozen importlib._bootstrap_external>", line 1374, in _path_importer_cache
  File "<frozen importlib._bootstrap_external>", line 1350, in _path_hooks
  File "<frozen importlib._bootstrap_external>", line 1632, in path_hook_for_FileFinder
  File "<frozen importlib._bootstrap_external>", line 1505, in __init__
FileNotFoundError: [Errno 2] No such file or directory

Original exception was:
Traceback (most recent call last):
  File "../failure.py", line 1, in <module>
    raise ValueError()
ValueError
```