SSHRemoteIO.remove_dir() does not error on error

[mih]

A test that documents that behavior is available from #81

[mih]

FileIO.remove_dir() is using Path.rmdir() which also errors:

>>> (p / 'mike').rmdir()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.11/pathlib.py", line 1157, in rmdir
    os.rmdir(self)
OSError: [Errno 39] Directory not empty: 'mike'