Make QtWebEngine imports consistent

Somehow on some platforms we end up with the import version of the wrong
module.

Change-Id: I6427f3f5375f2059d371c9a0fc035f1ec4195a49
Fixes: QTBUG-74566
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

examples/webengine/quicknanobrowser/BrowserDialog.qml

@@ -50,7 +50,7 @@
 
 import QtQuick 2.1
 import QtQuick.Window 2.2
-import QtWebEngine 1.7
+import QtWebEngine 1.9
 
 Window {
     id: window

examples/webengine/quicknanobrowser/DownloadView.qml

@@ -51,7 +51,7 @@
 import QtQuick 2.1
 import QtQuick.Controls 1.0
 import QtQuick.Controls.Styles 1.0
-import QtWebEngine 1.2
+import QtWebEngine 1.9
 import QtQuick.Layouts 1.0
 
 Rectangle {

examples/webengine/quicknanobrowser/main.cpp

@@ -89,7 +89,10 @@ int main(int argc, char **argv)
     Utils utils;
     appEngine.rootContext()->setContextProperty("utils", &utils);
     appEngine.load(QUrl("qrc:/ApplicationRoot.qml"));
-    QMetaObject::invokeMethod(appEngine.rootObjects().first(), "load", Q_ARG(QVariant, startupUrl()));
+    if (!appEngine.rootObjects().isEmpty())
+        QMetaObject::invokeMethod(appEngine.rootObjects().first(), "load", Q_ARG(QVariant, startupUrl()));
+    else
+        qFatal("Failed to load sources");
 
     return app.exec();
 }