unix/Daemon, playlist/pls, ...: remove unused Domain variables

src/Main.cxx

@@ -53,7 +53,6 @@
 #include "system/FatalError.hxx"
 #include "util/UriUtil.hxx"
 #include "util/Error.hxx"
-#include "util/Domain.hxx"
 #include "thread/Id.hxx"
 #include "thread/Slack.hxx"
 #include "lib/icu/Init.hxx"
@@ -126,8 +125,6 @@
 static constexpr unsigned DEFAULT_BUFFER_SIZE = 4096;
 static constexpr unsigned DEFAULT_BUFFER_BEFORE_PLAY = 10;
 
-static constexpr Domain main_domain("main");
-
 #ifdef ANDROID
 Context *context;
 #endif