detection of option-as-value doesn't work with store_or_None options

[boegel]

adding an extra test case to the existing test_option_as_value value demonstrates this:

diff --git a/test/generaloption.py b/test/generaloption.py
index 76f0bb2..73fdd47 100644
--- a/test/generaloption.py
+++ b/test/generaloption.py
@@ -899,6 +899,11 @@ debug=1
         self._match_testoption1_sysexit(['--store', '--foo', '--nosuchoptiondefinedfoobar'],
                                         "Value '--foo' starts with a '-'")

+        # test with store_or_None option
+        self._match_testoption1_sysexit(['--ext-pathliststorenone', 'b'],
+                                        "'-b' is a valid option")
+
+
 def suite():
     """ returns all the testcases in this module """
     return TestLoader().loadTestsFromTestCase(GeneralOptionTest)

@stdweird: for some reason unclear to me is_value_a_commandline_option gets () as value for th value parameter rather than the actual value being passed (b in this case), so the option-as-value goes undetected; however b does end up being assigned as the value for this option...