Do not set multivalue fields on create char properties

This ensures that the singleton is created when setting the account properties.
Singletons models return the default values when no model exists so the saved
multivalues are ignored if the singleton is not created.

issue6421
review36301002

account.py

@@ -2010,12 +2010,9 @@ class CreateChart(Wizard):
             account_receivable = self.properties.account_receivable
             account_payable = self.properties.account_payable
             config = Configuration(1)
-            config.set_multivalue(
-                'default_account_receivable',
-                account_receivable.id if account_receivable else None)
-            config.set_multivalue(
-                'default_account_payable',
-                account_payable.id if account_payable else None)
+            config.default_account_receivable = account_receivable
+            config.default_account_payable = account_payable
+            config.save()
         return 'end'