daemon: do not run complex code in a signal handler

instead, delegate the work to a one off thread
and notify it from the signal handler

src/daemon/daemon.cpp

@@ -136,7 +136,14 @@ bool t_daemon::run(bool interactive)
   {
     throw std::runtime_error{"Can't run stopped daemon"};
   }
-  tools::signal_handler::install(std::bind(&daemonize::t_daemon::stop_p2p, this));
+
+  std::atomic<bool> stop(false);
+  boost::thread([&stop, this] {
+    while (!stop)
+      epee::misc_utils::sleep_no_w(100);
+    this->stop_p2p();
+  }).detach();
+  tools::signal_handler::install([&stop](int){ stop = true; });
 
   try
   {