[fix] concat log error message

wizard/ebics_statement_rop_import_wizard.py

@@ -32,7 +32,7 @@ class EbicsStatementRopImport(models.TransientModel):
         })
         ebics_conf_id = ebics_mvt_obj.ebics_config_id
         ebics_wizard_act = ebics_mvt_obj.ebics_download()
-        self.log = """
+        self.log += """
             <strong><u>Téléchargement des mouvements enrichis<u></strong><br/>
             %s
             <hr/>
@@ -51,7 +51,7 @@ class EbicsStatementRopImport(models.TransientModel):
             'date_to': self.date_to,
         })
         ebics_rop_wizard_act = ebics_rop_obj.ebics_download()
-        self.log = """
+        self.log += """
             <strong><u>Téléchargement des mouvements ROP<u></strong><br/>
             %s
             <hr/>