Don't create a temporary list of values for qDeleteAll

It's enough to pass QHash as an input for qDeleteAll,
it will delete all values and won't touch keys.

Change-Id: I5a924f4d59787ac3fd1ffaf07709ab91ba96c7c6
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/marketplace/productlistmodel.cpp

@@ -193,7 +193,7 @@ SectionedProducts::SectionedProducts(QWidget *parent)
 
 SectionedProducts::~SectionedProducts()
 {
-    qDeleteAll(m_gridViews.values());
+    qDeleteAll(m_gridViews);
     delete m_productDelegate;
     delete m_gridModel;
 }