put back task propertysheet for trade condition. It was there since

years because trade condition was using class Path before. But
we will to consider if it makes sense to keep it (cleaning required,
but it has a lower priority)

git-svn-id: https://svn.erp5.org/repos/public/erp5/sandbox/amount_generator@34887 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Document/TradeCondition.py

@@ -70,6 +70,9 @@ class TradeCondition(MappedValue, AmountGeneratorMixin, VariatedMixin):
                       , PropertySheet.Arrow
                       , PropertySheet.TradeCondition
                       , PropertySheet.Order
+                      , PropertySheet.Task # XXX It is probably wrong to have
+                             # Task propertysheet, however many tests fails
+                             # if not present. Cleaning required.
                       )
 
     zope.interface.implements(interfaces.IAmountGenerator,