Check no account attribute.

This commit refs #21072

purchase.py

@@ -21,7 +21,7 @@ class PurchaseLine(metaclass=PoolMeta):
             for entry_acc in self.analytic_accounts:
                 accounts = AnalyticAccount.search(
                     self.get_party_analytic_account_domain(entry_acc.root))
-                if accounts and not entry_acc.account:
+                if accounts and not getattr(entry_acc, 'account', None):
                     entry_acc.account = accounts[0]
 
     @fields.depends('purchase', '_parent_purchase.company',