erp5_payroll_l10n_fr: fixup Base_redirect usage

bt5/erp5_payroll_l10n_fr/SkinTemplateItem/portal_skins/erp5_payroll_l10n_fr/PaySheetTransaction_addHolidayAcquisition.py

 holiday_acquisition = context.getCausalityRelatedValue(portal_type='Holiday Acquisition')
 if holiday_acquisition:
-  return holiday_acquisition.Base_redirect('view', context.Base_translateString('Holiday Acquisition is already created'))
+  return holiday_acquisition.Base_redirect('view', keep_items={'portal_status_message': context.Base_translateString('Holiday Acquisition is already created')})
 
 employee = context.getSourceSectionValue()
 stop_date = context.getStopDate()
@@ -24,5 +24,4 @@ holiday_acquisition = context.holiday_acquisition_module.newContent(
 )
 
 holiday_acquisition.plan()
-return holiday_acquisition.Base_redirect('view',
-  context.Base_translateString('Holiday Acquisition is created'))
+return holiday_acquisition.Base_redirect('view', keep_items={'portal_status_message': context.Base_translateString('Holiday Acquisition is created')})