Fix test for new version of urllib that uses HTTPConnection directly.

Changes the way the httplib classes are stubbed out.
diff --git a/Lib/test/test_urllib.py b/Lib/test/test_urllib.py
index a31bb52..dde5d58 100644
--- a/Lib/test/test_urllib.py
+++ b/Lib/test/test_urllib.py
@@ -111,11 +111,11 @@
         class FakeHTTPConnection(httplib.HTTPConnection):
             def connect(self):
                 self.sock = FakeSocket(fakedata)
-        assert httplib.HTTP._connection_class == httplib.HTTPConnection
-        httplib.HTTP._connection_class = FakeHTTPConnection
+        self._connection_class = httplib.HTTPConnection
+        httplib.HTTPConnection = FakeHTTPConnection
 
     def unfakehttp(self):
-        httplib.HTTP._connection_class = httplib.HTTPConnection
+        httplib.HTTPConnection = self._connection_class
 
     def test_read(self):
         self.fakehttp(b"Hello!")