Remove showNotification function

src/notifications/Manager.h

@@ -47,7 +47,6 @@ public:
 
 private:
         QDBusInterface dbus;
-        uint showNotification(const QString summary, const QString text, const QImage image);
         void closeNotification(uint id);
 
         // notification ID to (room ID, event ID)

src/notifications/ManagerLinux.cpp

@@ -86,18 +86,6 @@ NotificationsManager::postNotification(const QString &roomid,
     });
 }
 
-uint
-NotificationsManager::showNotification(const QString summary,
-                                       const QString text,
-                                       const QImage image)
-{
-    Q_UNUSED(summary)
-    Q_UNUSED(text)
-    Q_UNUSED(image)
-
-    return 0;
-}
-
 void
 NotificationsManager::closeNotification(uint id)
 {