[FIX] payment_transfer: hack the broken hack

Put bank data back in transfer providers. Otherwise users are very very
sad to not have a default message containing bank accounts data.

addons/payment_transfer/models/payment.py

@@ -46,6 +46,13 @@ class TransferPaymentAcquirer(models.Model):
             values['post_msg'] = self._format_transfer_data()
         return super(TransferPaymentAcquirer, self).create(values)
 
+    @api.multi
+    def write(self, values):
+        """ Hook in write to create a default post_msg. See create(). """
+        if all(not acquirer.post_msg and acquirer.provider != 'transfer' for acquirer in self) and values.get('provider') == 'transfer':
+            values['post_msg'] = self._format_transfer_data()
+        return super(TransferPaymentAcquirer, self).write(values)
+
 
 class TransferPaymentTransaction(models.Model):
     _inherit = 'payment.transaction'