custom dtor is unnecessary

Change-Id: I2b9d167628995747a6c1b032f3461d988ed485e5

vcl/inc/unx/saldisp.hxx

@@ -120,7 +120,6 @@ public:
                  SalX11Screen       nXScreen );
     SalColormap( sal_uInt16         nDepth );
     SalColormap();
-    ~SalColormap();
 
     inline  Colormap            GetXColormap() const { return m_hColormap; }
     inline  const SalDisplay*   GetDisplay() const { return m_pDisplay; }

vcl/unx/generic/app/saldisp.cxx

@@ -2705,14 +2705,6 @@ SalColormap::SalColormap( sal_uInt16 nDepth )
     }
 }
 
-SalColormap::~SalColormap()
-{
-#ifdef DBG_UTIL
-    m_hColormap      = None;
-    m_pDisplay       = nullptr;
-#endif
-}
-
 void SalColormap::GetPalette()
 {
     Pixel i;