When search_key is None, result must be set to None. Fixes an UnboundLocalError when it happens.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@25927 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ZSQLCatalog/SQLCatalog.py

@@ -1956,6 +1956,7 @@ class Catalog(Folder,
     if search_key is None:
       # Unknown, skip loudly
       LOG('SQLCatalog', WARNING, 'Unknown column %r, skipped.' % (key, ))
+      result = None
     else:
       if related_key_definition is None:
         build_key = search_key