Replace Python 2 tmpdir removal workarounds

Author: hugovk

tests/conftest.py

@@ -129,10 +129,7 @@ def tmpdir_factory(request, tmpdir_factory):
     """
     yield tmpdir_factory
     if not request.config.getoption("--keep-tmpdir"):
-        shutil.rmtree(
-            tmpdir_factory.getbasetemp(),
-            ignore_errors=True,
-        )
+        tmpdir_factory.getbasetemp().remove(ignore_errors=True)
 
 
 @pytest.fixture