Remove last traces of cStringIO.
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index 14f55fb..e9570e9 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -297,7 +297,7 @@
         self.assert_(isinstance(vi[4], int))
 
     def test_43581(self):
-        # Can't use sys.stdout, as this is a cStringIO object when
+        # Can't use sys.stdout, as this is a StringIO object when
         # the test runs under regrtest.
         self.assertEqual(sys.__stdout__.encoding, sys.__stderr__.encoding)