Revert "ossaudio: do not enable by default"

This reverts commit c905c501.

There is a better fix for the issue at hand.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

audio/ossaudio.c

@@ -932,7 +932,7 @@ struct audio_driver oss_audio_driver = {
     .init           = oss_audio_init,
     .fini           = oss_audio_fini,
     .pcm_ops        = &oss_pcm_ops,
-    .can_be_default = 0,
+    .can_be_default = 1,
     .max_voices_out = INT_MAX,
     .max_voices_in  = INT_MAX,
     .voice_size_out = sizeof (OSSVoiceOut),