A few odds and ends after lookahead patch (#215)

src/scanner.cpp

@@ -1078,6 +1078,9 @@ namespace lws
         if (!lws_server_addr.empty())
           rpc::scanner::server::start_acceptor(server, lws_server_addr, std::move(lws_server_pass));
 
+        // This is a hack to prevent racy shutdown
+        boost::asio::post(self.io_, [&self] () { if (!self.is_running()) self.stop(); });
+
         // Blocks until sigint, local scanner issue, storage issue, or exception
         self.io_.restart();
         self.io_.run();