Revert "Main: start IO threads before initializing the rest"

This reverts commit abc8420.  This
was a bad idea, too, because it broke daemonization.

Author: MaxKellermann

src/Main.cxx

@@ -329,9 +329,6 @@ MainConfigured(const CommandLineOptions &options,
 	Instance instance;
 	global_instance = &instance;
 
-	instance.io_thread.Start();
-	instance.rtio_thread.Start();
-
 #ifdef ENABLE_NEIGHBOR_PLUGINS
 	instance.neighbors = std::make_unique<NeighborGlue>();
 	instance.neighbors->Init(raw_config,
@@ -424,6 +421,9 @@ MainConfigured(const CommandLineOptions &options,
 	};
 #endif
 
+	instance.io_thread.Start();
+	instance.rtio_thread.Start();
+
 #ifdef ENABLE_NEIGHBOR_PLUGINS
 	if (instance.neighbors != nullptr)
 		instance.neighbors->Open();