Fixed getLexicon so that it can properly raise an error when it canno…

…t find the proper lexicon object.

ZCTextIndex.py

@@ -124,7 +124,7 @@ def getLexicon(self):
             lexicon = getattr(aq_parent(aq_inner(self)), self.lexicon_id)
             if not ILexicon.isImplementedBy(lexicon):
                 raise TypeError('Object "%s" is not a ZCTextIndex Lexicon'
-                                % lexicon.getId())
+                                % repr(lexicon))
             self._v_lexicon = lexicon
             return lexicon