ALSAAudioInput: use snd_pcm_drop() instead of snd_pcm_drain() in clas…

…s destructor

snd_pcm_drain() waits for all pending frames to be played.

snd_pcm_drop() is better in our case, because we want the PCM stream to be stopped immediately.

src/mumble/ALSAAudio.cpp

@@ -373,7 +373,7 @@ void ALSAAudioInput::run() {
 		}
 	}
 
-	snd_pcm_drain(capture_handle);
+	snd_pcm_drop(capture_handle);
 	snd_pcm_close(capture_handle);
 
 	qWarning("ALSAAudioInput: Releasing ALSA Mic.");