MenuItem: Connect to own action's 'shortcutChanged' signal

Otherwise, we won't be setting the shortcut on the platform item.

Task-number: QTBUG-31368
Change-Id: I333b903719d6e95a411f4f423c0e9b8ce15e640e
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

src/controls/qquickmenuitem.cpp

@@ -401,6 +401,7 @@ QQuickMenuItem::QQuickMenuItem(QObject *parent)
 {
     connect(this, SIGNAL(__textChanged()), this, SIGNAL(textChanged()));
 
+    connect(action(), SIGNAL(shortcutChanged(QString)), this, SLOT(updateShortcut()));
     connect(action(), SIGNAL(triggered()), this, SIGNAL(triggered()));
     connect(action(), SIGNAL(toggled(bool)), this, SLOT(updateChecked()));
     if (platformItem())