input/ffmpeg: include cleanup

src/input/plugins/FfmpegInputPlugin.cxx

 /*
- * Copyright 2003-2018 The Music Player Daemon Project
+ * Copyright 2003-2019 The Music Player Daemon Project
  * http://www.musicpd.org
  *
  * This program is free software; you can redistribute it and/or modify
@@ -22,12 +22,10 @@
 
 #include "FfmpegInputPlugin.hxx"
 #include "lib/ffmpeg/Init.hxx"
-#include "lib/ffmpeg/Domain.hxx"
 #include "lib/ffmpeg/Error.hxx"
 #include "../InputStream.hxx"
 #include "../InputPlugin.hxx"
 #include "PluginUnavailable.hxx"
-#include "util/ASCII.hxx"
 
 extern "C" {
 #include <libavformat/avio.h>