CMenueWidget: get header height directly from header object

Origin commit data
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Commit: 6de4e58535
Author: Thilo Graf <dbt@novatux.de>
Date: 2019-03-31 (Sun, 31 Mar 2019)

src/gui/widget/menue.h

@@ -608,6 +608,7 @@ class CMenuWidget : public CMenuTarget, public CComponentsSignals
 		void saveScreen();
 		void restoreScreen();
 		void setMenuPos(const int& menu_width);
+		void initHeader();
 
 	public:
 		CMenuWidget();