adjust the minimal menu item height to be lesser than the menubar height; some code cleanup

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51079 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/ownerdrw.h

@@ -164,7 +164,6 @@ private:
             m_bmpDisabled;
 
   size_t    m_nHeight,      // font height
-            m_nMinHeight,   // minimum height, as determined by user's system settings
             m_nMarginWidth; // space occupied by bitmap to the left of the item
 };