server helper: Update comment and code

Signed-off-by: Masahiro Nakagawa <[email protected]>

lib/fluent/plugin_helper/server.rb

@@ -355,8 +355,9 @@ def server_create_tcp_socket(shared, bind, port)
         sock = if shared
                  server_socket_manager_client.listen_tcp(bind, port)
                else
-                 # TCPServer.new doesn't set IPV6_V6ONLY flag, so use tcp_server_sockets instead.
-                 tsock = Addrinfo.tcp(bind, port).listen(::Socket::SOMAXCONN)
+                 # TCPServer.new doesn't set IPV6_V6ONLY flag, so use Addrinfo class instead.
+                 # backlog will be set by the caller, we don't need to set backlog here
+                 tsock = Addrinfo.tcp(bind, port).listen
                  tsock.autoclose = false
                  TCPServer.for_fd(tsock.fileno)
                end