ProjectNodes: Remove unused member

Change-Id: Iaeca64c025a870ce83f9d806fdd3e086599046d5
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/projectexplorer/projectnodes.h

@@ -360,7 +360,6 @@ public:
 
 private:
     Project *m_project;
-    QList<Node *> m_nodes;
 };
 
 } // namespace ProjectExplorer