Infinite loop when walking through archive containing . (dot) entry

STEPS
1. Create an archive:

    ```bash
    mkdir empty_dir
    tar -cf fs_test_infinite_loop.tar -C empty_dir .
    ```
    
2. Walk the archive using `fs.WalkDir` function.

EXPECTED:
The walk function is called once.
OBSERVED:
The walk function is in an infinite loop.