Use root to update anglo_saxon_quantity

review628002
(transplanted from b3dd5552c16e4c0012a1e5a9d2c0719d123bb137)

stock.py

@@ -4,6 +4,7 @@ from decimal import Decimal
 from trytond.model import ModelView, ModelSQL, fields
 from trytond.pyson import Eval
 from trytond.pool import Pool
+from trytond.transaction import Transaction
 
 
 class Move(ModelSQL, ModelView):
@@ -70,10 +71,11 @@ class Move(ModelSQL, ModelView):
                 move_cost_price = move.cost_price
             cost += move_cost_price * Decimal(str(move_qty))
 
-            self.write(move.id, {
-                'anglo_saxon_quantity': ((move.anglo_saxon_quantity or 0.0)
-                    + move_qty),
-                })
+            with Transaction().set_user(0, set_context=True):
+                self.write(move.id, {
+                    'anglo_saxon_quantity': ((move.anglo_saxon_quantity or 0.0)
+                        + move_qty),
+                    })
 
         if consumed_qty < total_qty:
             qty = total_qty - consumed_qty