Use context to check model and field access

issue4081
review8481002

purchase.py

@@ -162,8 +162,7 @@ class PurchaseLine:
                     accounts = []
                     if not line.analytic_accounts:
                         # Create missing selection
-                        with Transaction().set_user(0):
-                            selection, = Selection.create([{}])
+                        selection, = Selection.create([{}])
                         cls.write([line], {
                             'analytic_accounts': selection.id,
                             })