[FIX] product_ur and journal_ur referenced before assignment in refund

wizard/scop_bordereau_refund_wizard.py

@@ -153,6 +153,7 @@ class ScopBordereauRefundWizard(models.TransientModel):
             )
 
         # CREATE REFUND
+        product_ur = journal_ur = False
         if partner_id.ur_id.id == ur_hdf:
             product_ur = self.env.company.contribution_hdf_id
             journal_ur = self.env.user.company_id.journal_ur_hdf_id