nmbug-status: replace __values__() with values() in OrderedDict stub

Python dict() object does not have __values__() function which
OrderedDict().values() (the stub provided in nmbug-status) could call
to provide ordered list of values. By renaming this thinko to
values() will make our stub work as expected -- dict items listed out
in order those were added to the dictionary.

devel/nmbug/nmbug-status

@@ -41,7 +41,7 @@ if not hasattr(collections, 'OrderedDict'):  # Python 2.6 or earlier
             super(_OrderedDict, self).__setitem__(key, value)
             self._keys.append(key)
 
-        def __values__(self):
+        def values(self):
             for key in self._keys:
                 yield self[key]