Fixed trailing whitespace in test file.

tests/test_filterset.py

@@ -746,7 +746,7 @@ def test_creating_with_request(self):
         m = mock.Mock()
         f = self.F(request=m)
         self.assertEqual(f.request, m)
-    
+
     def test_creating_with_no_data_default(self):
         f = self.F()
         self.assertIsInstance(f.data, MultiValueDict)