Return listenbuffer behavior

Now we're start to serve early, but all Accept calls are intercepted by
listenbuffer or systemd socket.

Signed-off-by: Alexander Morozov <lk4d4@docker.com>

api/server/server.go

@@ -76,11 +76,10 @@ func (s *Server) Close() {
 }
 
 // ServeAPI loops through all initialized servers and spawns goroutine
-// with Server method for each. It sets CreateMux() as Handler also.
+// with Serve() method for each.
 func (s *Server) ServeAPI() error {
 	var chErrors = make(chan error, len(s.servers))
 	for _, srv := range s.servers {
-		srv.srv.Handler = s.CreateMux()
 		go func(srv *HTTPServer) {
 			var err error
 			logrus.Infof("API listen on %s", srv.l.Addr())
@@ -162,9 +161,13 @@ func (s *Server) makeHTTPHandler(handler httputils.APIFunc) http.HandlerFunc {
 }
 
 // InitRouters initializes a list of routers for the server.
+// Sets those routers as Handler for each server.
 func (s *Server) InitRouters(d *daemon.Daemon) {
 	s.addRouter(local.NewRouter(d))
 	s.addRouter(network.NewRouter(d))
+	for _, srv := range s.servers {
+		srv.srv.Handler = s.CreateMux()
+	}
 }
 
 // addRouter adds a new router to the server.