Update account_invoice.py

The module is breaking any other module that calls the _compute_amount method on account_move.
I'm adding the line that fix that issue.

sale_discount_total/models/account_invoice.py

@@ -60,6 +60,7 @@ class AccountInvoice(models.Model):
         'line_ids.payment_id.state',
         'line_ids.full_reconcile_id')
     def _compute_amount(self):
+        super(AccountInvoice, self)._compute_amount()
         for move in self:
             total_untaxed, total_untaxed_currency = 0.0, 0.0
             total_tax, total_tax_currency = 0.0, 0.0