KItemListSizeHintResolver: remove no longer used member

src/kitemviews/private/kitemlistsizehintresolver.h

@@ -38,7 +38,6 @@ private:
     const KItemListView* m_itemListView;
     mutable QVector<qreal> m_logicalHeightHintCache;
     mutable qreal m_logicalWidthHint;
-    mutable qreal m_logicalHeightHint;
     mutable qreal m_minHeightHint;
     bool m_needsResolving;
 };