we should add Task propertysheet to packing list because a packing list needs start and stop dates

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@16411 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/PackingList.py

@@ -77,6 +77,7 @@ class PackingList(Delivery):
                       , PropertySheet.Arrow
                       , PropertySheet.Comment
                       , PropertySheet.Movement
+                      , PropertySheet.Task
                       )
 
     security.declareProtected(Permissions.AccessContentsInformation,