output/Thread: KILL implicitly closes and disables the AudioOutput

Reduce shutdown latency by two commands per output.

src/output/MultipleOutputs.cxx

@@ -43,14 +43,8 @@ MultipleOutputs::MultipleOutputs(MixerListener &_mixer_listener)
 
 MultipleOutputs::~MultipleOutputs()
 {
-	for (auto i : outputs) {
-		{
-			const ScopeLock lock(i->mutex);
-			i->DisableWait();
-		}
-
+	for (auto i : outputs)
 		i->Finish();
-	}
 }
 
 static AudioOutput *

src/output/OutputControl.cxx

@@ -276,9 +276,8 @@ AudioOutput::StopThread()
 void
 AudioOutput::Finish()
 {
-	LockCloseWait();
-
-	assert(!fail_timer.IsDefined());
+	if (mixer != nullptr)
+		mixer_auto_close(mixer);
 
 	if (thread.IsDefined())
 		StopThread();

src/output/OutputThread.cxx

@@ -642,6 +642,7 @@ AudioOutput::Task()
 			continue;
 
 		case Command::KILL:
+			Disable();
 			pipe.Cancel();
 			CommandFinished();
 			return;