Display product customer for line action of amendment

issue11524
review421261003
(grafted from 6e0e28a8c9697c2cca1ecc51389251fd3f63c9b4)

--HG--
branch : 6.0

sale.py

@@ -79,7 +79,7 @@ class AmendmentLine(metaclass=PoolMeta):
             ('party', '=', Eval('party', -1)),
             ],
         states={
-            'invisible': Eval('action') != 'product',
+            'invisible': Eval('action') != 'line',
             },
         depends=['action', 'product', 'party'])