BusinessTemplate: fix NameError on view when erp5_forge is not updated

This only happens in rare condition:
 * products where updated and ERP5VCS is moved to portal_components
 * everything is updated except erp5_forge
 * preferences for VCS working copies is set

product/ERP5/Document/BusinessTemplate.py

@@ -5816,8 +5816,11 @@ Business Template is a set of definitions, such as skins, portal types and categ
       # could be moved to Products.ERP5.Base.Base
       try:
         from erp5.component.module.WorkingCopy import NotAWorkingCopyError
+      except ImportError:
+        return False
+      try:
         return self.getVcsTool().reference in vcs
-      except (ImportError, NotAWorkingCopyError):
+      except NotAWorkingCopyError:
         return None in vcs
 
     security.declareProtected(Permissions.ManagePortal, 'export')