use ResetClipping() instead of simply setting m_clipping to false; added call to it to wxDCBase::DestroyClippingRegion() so that some ports don't have to define their own version of it at all

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@27107 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk1/dc.h

@@ -46,9 +46,6 @@ public:
 
     void SetColourMap( const wxPalette& palette ) { SetPalette(palette); };
 
-    // the first two must be overridden and called
-    virtual void DestroyClippingRegion();
-
     // Resolution in pixels per logical inch
     virtual wxSize GetPPI() const;