Fixed crash on Windows

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403441

src/audio/SDL_audio.c

@@ -625,7 +625,9 @@ SDL_AudioInit(const char *driver_name)
             initialized = 1;
             best_choice = i;
         } else if (rc == 1) {   /* init'd, but can't see any devices. */
+            if (current_audio.impl.Deinitialize) {
                 current_audio.impl.Deinitialize();
+            }
             if (best_choice == -1) {
                 best_choice = i;
             }