Fix style.

dulwich/porcelain.py

@@ -429,7 +429,7 @@ def clone(
             DeprecationWarning,
             stacklevel=3,
         )
-        errstream = outstream
+        # TODO(jelmer): Capture logging output and stream to errstream
 
     if checkout is None:
         checkout = not bare

dulwich/tests/test_index.py

@@ -30,7 +30,6 @@ import stat
 import struct
 import sys
 import tempfile
-import warnings
 
 from dulwich.index import (
     Index,
@@ -64,9 +63,6 @@ from dulwich.tests import (
     TestCase,
     skipIf,
 )
-from dulwich.tests.utils import (
-    setup_warning_catcher,
-)
 
 
 def can_symlink():