ZODB Components: Backward compatibility with instances before ZODB Interfaces/Mixins (e84d2b51).

e84d2b51 introduced template_{interface,mixin}_id BusinessTemplate properties
in erp5_property_sheets without keeping backward compatibility and thus
preventing update:
  Module Products.ERP5.Tool.TemplateTool, line 1446, in upgradeSite
    update_catalog=update_catalog)
  Module Products.ERP5.Tool.TemplateTool, line 1289, in updateBusinessTemplateFromUrl
    imported_bt5 = self.download(url = download_url, id = id)
  Module Products.ERP5.Tool.TemplateTool, line 382, in download
    bt = self._download_local(path, id)
  Module Products.ERP5.Tool.TemplateTool, line 328, in _download_local
    bt.importFile(path)
  Module Products.ERP5.Document.BusinessTemplate, line 5887, in importFile
    self.storeTemplateItemData()
  Module Products.ERP5.Document.BusinessTemplate, line 5165, in storeTemplateItemData
    InterfaceTemplateItem(self.getTemplateInterfaceIdList())
AttributeError: getTemplateInterfaceIdList

product/ERP5/Document/BusinessTemplate.py

@@ -5161,10 +5161,6 @@ Business Template is a set of definitions, such as skins, portal types and categ
           ModuleTemplateItem(self.getTemplateModuleIdList())
       self._document_item = \
           DocumentTemplateItem(self.getTemplateDocumentIdList())
-      self._interface_item = \
-          InterfaceTemplateItem(self.getTemplateInterfaceIdList())
-      self._mixin_item = \
-          MixinTemplateItem(self.getTemplateMixinIdList())
       self._property_sheet_item = \
           PropertySheetTemplateItem(self.getTemplatePropertySheetIdList(),
                                     context=self)
@@ -5246,6 +5242,10 @@ Business Template is a set of definitions, such as skins, portal types and categ
         self._catalog_security_uid_column_item = \
           CatalogSecurityUidColumnTemplateItem(
                self.getTemplateCatalogSecurityUidColumnList())
+        self._interface_item = \
+          InterfaceTemplateItem(self.getTemplateInterfaceIdList())
+        self._mixin_item = \
+          MixinTemplateItem(self.getTemplateMixinIdList())
       except AttributeError:
         # be backwards compatible with old zope instances which
         # do not contain recent version of erp5_property_sheets