we need a fallback list when both getPreferredWorkingCopyList() and...

we need a fallback list when both getPreferredWorkingCopyList() and getPreferredSubversionWorkingCopyList() return None, otherwise we get the following exception:
TypeError: 'NoneType' object is not iterable


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@43661 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/BusinessTemplate.py

@@ -5099,7 +5099,7 @@ Business Template is a set of definitions, such as skins, portal types and categ
       from App.config import getConfiguration
       instance_home = getConfiguration().instancehome
       for path in (preferences.getPreferredWorkingCopyList() or # BBB
-                   preferences.getPreferredSubversionWorkingCopyList()):
+                   preferences.getPreferredSubversionWorkingCopyList() or ['bt5']):
         if not os.path.isabs(path):
           path = os.path.join(instance_home, path)
         bt_path = os.path.join(path, bt_name)