Fix deprecation warning for dulwich.clone.

dulwich/porcelain.py

@@ -185,7 +185,8 @@ def clone(source, target=None, bare=False, checkout=None, errstream=sys.stdout,
     """
     if outstream is not None:
         import warnings
-        warnings.warn("outstream= has been deprecated in favour of errstream=.", DeprecationWarning)
+        warnings.warn("outstream= has been deprecated in favour of errstream=.", DeprecationWarning,
+                stacklevel=3)
         errstream = outstream
 
     if checkout is None:

dulwich/tests/test_porcelain.py

@@ -162,10 +162,10 @@ class CloneTests(PorcelainTestCase):
         (c1, ) = build_commit_graph(self.repo.object_store, commit_spec, trees)
         self.repo.refs[b"refs/heads/master"] = c1.id
         target_path = tempfile.mkdtemp()
-        outstream = BytesIO()
+        errstream = BytesIO()
         self.addCleanup(shutil.rmtree, target_path)
         self.assertRaises(ValueError, porcelain.clone, self.repo.path,
-            target_path, checkout=True, bare=True, outstream=outstream)
+            target_path, checkout=True, bare=True, errstream=errstream)
 
 
 class InitTests(TestCase):