sdl2: Fix dead keyboard after fullsceen

Signed-off-by: Jindrich Makovicka <makovick@gmail.com>
Message-Id: <20171112193032.9724-7-makovick@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/sdl2.c

@@ -442,6 +442,7 @@ static void handle_keyup(SDL_Event *ev)
             sdl2_reset_keys(scon);
             return;
         }
+        sdl2_reset_keys(scon);
         gui_keysym = 0;
     }
     if (!gui_keysym) {