Use alternate spelling for flavor attribute.

distutils/tests/test_dir_util.py

@@ -124,7 +124,7 @@ class FailPath(pathlib.Path):
             def mkdir(self, *args, **kwargs):
                 raise OSError("Failed to create directory")
 
-            _flavor = (
+            _flavour = (
                 pathlib._windows_flavour if os.name == 'nt' else pathlib._posix_flavour
             )