unit test fix

The fixed unit test explicitely checks output that came from the Python
argparse module. This output changed for newer versions.

doc/tests/test_doctests.py

@@ -153,7 +153,7 @@ class DocTests(unittest.TestCase):
                          "Place the description of your script right in the file and import")
         self.assertEqual(out_lines[3].strip(),
                          "it via '__doc__' as description to the parser ('-h', '--help').")
-        self.assertEqual(out_lines[5].strip(), "optional arguments:")
+        self.assertTrue(out_lines[5].strip() in ["optional arguments:", "options:"])
         self.assertGreater(len(out_lines), 5)
 
     def testCoreMsgError(self):