impr: Keyboard Layout DBus API: expose switchToNextLayout() method

P-W part:
"Keyboard Layout plugin: passthrough DBus switchToNextLayout() method
to QML applet"

kcms/keyboard/keyboard_daemon.cpp

@@ -211,7 +211,7 @@ void KeyboardDaemon::switchToNextLayout()
         QStringLiteral("org.kde.osdService"),
         QStringLiteral("kbdLayoutChanged"));
 
-        msg << Flags::getShortText(newLayout, keyboardConfig);
+        msg << Flags::getLongText(newLayout, rules);
 
         QDBusConnection::sessionBus().asyncCall(msg);
 }

kcms/keyboard/keyboard_daemon.h

@@ -52,7 +52,6 @@ class Q_DECL_EXPORT KeyboardDaemon : public KDEDModule
     void setupTrayIcon();
 
 private Q_SLOTS:
-	void switchToNextLayout();
     void configureKeyboard();
     void configureMouse();
     void layoutChanged();
@@ -60,6 +59,7 @@ private Q_SLOTS:
 	bool setLayout(QAction* action);
 
 public Q_SLOTS:
+	Q_SCRIPTABLE void switchToNextLayout();
 	Q_SCRIPTABLE bool setLayout(const QString& layout);
 	Q_SCRIPTABLE QString getCurrentLayout();
 	Q_SCRIPTABLE QString getCurrentLayoutLongName() const;