tests: Fix skipping mkdir-with-parents-permission test

If the user has CAP_DAC_OVERRIDE or similar (for example, if running the tests as root), the mkdir-with-parents-permission test is skipped.

The check for CAP_DAC_OVERRIDE was by creating a subdirectory of the test directory. That subdirectory, however, was never removed, which caused a ‘directory not empty’ error when trying to delete the test directory.

Fix that by correctly deleting the subdirectory if skipping the test.

Signed-off-by: Philip Withnall withnall@endlessm.com