Minor crash bugfix

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%4035

src/video/SDL_video.c

@@ -1134,6 +1134,9 @@ int SDL_SetPalette(SDL_Surface *screen, int which,
 	int gotall;
 	int palsize;
 
+	if ( ! current_video ) {
+		return 0;
+	}
 	if ( screen != SDL_PublicSurface ) {
 	        /* only screens have physical palettes */
 	        which &= ~SDL_PHYSPAL;