Removed not needed SDL_WINDOW_SHOWN from iOS example programs.

See bug #1667.

Xcode-iOS/Demos/src/accelerometer.c

@@ -172,7 +172,7 @@ main(int argc, char *argv[])
 
     /* create main window and renderer */
     window = SDL_CreateWindow(NULL, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT,
-                                SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN |
+                                SDL_WINDOW_OPENGL |
                                 SDL_WINDOW_BORDERLESS);
     renderer = SDL_CreateRenderer(window, 0, 0);