Fixed memory corruption in SW_RenderReadPixels()

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%404175

src/video/SDL_surface.c

@@ -961,7 +961,7 @@ int SDL_ConvertPixels(int width, int height,
     rect.x = 0;
     rect.y = 0;
     rect.w = width;
-    rect.h = width;
+    rect.h = height;
     return SDL_LowerBlit(&src_surface, &rect, &dst_surface, &rect);
 }