winstore: Gracefuly fail when no IAudioClient is provided

modules/audio_output/winstore.c

@@ -172,14 +172,17 @@ static int Open(vlc_object_t *obj)
 {
     audio_output_t *aout = (audio_output_t *)obj;
 
+    IAudioClient* client = var_InheritInteger(aout, "winstore-audioclient");
+    if (client == NULL)
+        return VLC_EGENERIC;
+
     aout_sys_t *sys = malloc(sizeof (*sys));
     if (unlikely(sys == NULL))
         return VLC_ENOMEM;
 
     aout->sys = sys;
     sys->stream = NULL;
-    sys->client = var_InheritInteger(aout, "winstore-audioclient");
-    assert(sys->client != NULL);
+    sys->client = client;
     aout->start = Start;
     aout->stop = Stop;
     aout->time_get = TimeGet;