QmlDesigner.MetaInfo: Avoid duplicated properties

For some reason ApplicationWindow seems to be twice in the type hierarchy.
This means all properties specific to ApplicationWindow were
duplicated. This patch avoids adding a property twice.

Task-number: QTCREATORBUG-12910
Change-Id: I8a06fa15778335be8c6977369ece94385b25487c
Reviewed-by: Robert Loehning <robert.loehning@digia.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>

src/plugins/qmldesigner/designercore/metainfo/nodemetainfo.cpp

@@ -786,10 +786,12 @@ void NodeMetaInfoPrivate::setupLocalPropertyInfo(QList<PropertyInfo> localProper
 void NodeMetaInfoPrivate::setupPropertyInfo(QList<PropertyInfo> propertyInfos)
 {
     foreach (const PropertyInfo &propertyInfo, propertyInfos) {
+        if (!m_properties.contains(propertyInfo.first)) {
             m_properties.append(propertyInfo.first);
             m_propertyTypes.append(propertyInfo.second);
         }
     }
+}
 
 bool NodeMetaInfoPrivate::isPropertyWritable(const PropertyName &propertyName) const
 {