QmlDesigner: QPixmap::grabWidget() is depricated in Qt 5

Change-Id: Ie74c61704573f517586c5acb7a87826942ee7dd3
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

src/plugins/qmldesigner/components/propertyeditor/basicwidgets.cpp

@@ -1294,7 +1294,12 @@ void QGroupBoxDeclarativeUI::collapse()
     m_oldMinHeight =gb->minimumHeight();
     if (!m_expanded)
         return;
-    m_contens = QPixmap::grabWidget (gb, 5, 5, gb->width() - 5, gb->height() - 5);
+
+#if QT_VERSION < 0x050000
+    m_contens = QPixmap::grabWidget(gb, 5, 5, gb->width() - 5, gb->height() - 5);
+#else
+    m_contens = gb->grab(QRect(5, 5, gb->width() - 5, gb->height() - 5));
+#endif
     gb->setPixmap(m_contens,1);
     hideChildren();
     m_expanded = false;