[FIX] account: substract total amount of credit notes in the counts reported on dashboard

The refactoring made for v11 at commit 414ea47fd5 summed the amounts of every invoice, credit note or not. This lead to wrong amounts in dashboard, as credit notes have positive total amounts, just like regular invoices.

(Fixes this ticket: https://www.odoo.com/web#id=1828003&view_type=form&model=project.task&action=333&active_id=49&menu_id=4720)

addons/account/models/account_journal_dashboard.py

@@ -224,7 +224,7 @@ class account_journal(models.Model):
         data as its first element, and the arguments dictionary to use to run
         it as its second.
         """
-        return ("""SELECT state, amount_total, currency_id AS currency
+        return ("""SELECT state, amount_total, currency_id AS currency, type
                   FROM account_invoice
                   WHERE journal_id = %(journal_id)s AND state = 'open';""", {'journal_id':self.id})
 
@@ -234,7 +234,7 @@ class account_journal(models.Model):
         gather the bills in draft state data, and the arguments
         dictionary to use to run it as its second.
         """
-        return ("""SELECT state, amount_total, currency_id AS currency
+        return ("""SELECT state, amount_total, currency_id AS currency, type
                   FROM account_invoice
                   WHERE journal_id = %(journal_id)s AND state = 'draft';""", {'journal_id':self.id})
 
@@ -247,7 +247,9 @@ class account_journal(models.Model):
         for result in results_dict:
             cur = self.env['res.currency'].browse(result.get('currency'))
             rslt_count += 1
-            rslt_sum += cur.compute(result.get('amount_total'), target_currency)
+
+            type_factor = result.get('type') in ('in_refund', 'out_refund') and -1 or 1
+            rslt_sum += type_factor * cur.compute(result.get('amount_total'), target_currency)
         return (rslt_count, rslt_sum)
 
     @api.multi