Remove deprecated method

agents/newmailnotifier/specialnotifierjob.cpp

@@ -138,7 +138,7 @@ void SpecialNotifierJob::emitNotification(const QPixmap &pixmap)
     }
 
     if (NewMailNotifierAgentSettings::showButtonToDisplayMail()) {
-        KNotification *notification = new KNotification(QStringLiteral("new-email"), nullptr,
+        KNotification *notification = new KNotification(QStringLiteral("new-email"),
                                                         NewMailNotifierAgentSettings::keepPersistentNotification() ? KNotification::Persistent
                                                         | KNotification::SkipGrouping : KNotification::CloseOnTimeout);
         notification->setText(result.join(QLatin1Char('\n')));