canvas: MSVC: pragma warning: make more specific, remove obsolete

Change-Id: I0d23c789dd3cbb21a18383988dd6b24318fda225
Reviewed-on: https://gerrit.libreoffice.org/48959Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

canvas/source/directx/dx_winstuff.hxx

@@ -49,13 +49,8 @@ typedef IDirect3DSurface9 surface_type;
 #define min(a,b) (((a) < (b)) ? (a) : (b))
 #endif
 
-#pragma warning(push, 1)
-#pragma warning(disable: 4458)
-
 #include <gdiplus.h>
 
-#pragma warning(pop)
-
 #undef max
 #undef min