server: ignore server closed error

no harm in ignoring this error, it comes from the underlying kube
stream server and we have no power on it as we don't own the listener
(containerd/cri also ignores it)

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

server/server.go

@@ -383,7 +383,7 @@ func New(ctx context.Context, config *Config) (*Server, error) {
 	s.stream.streamServerCloseCh = make(chan struct{})
 	go func() {
 		defer close(s.stream.streamServerCloseCh)
-		if err := s.stream.streamServer.Start(true); err != nil {
+		if err := s.stream.streamServer.Start(true); err != nil && err != http.ErrServerClosed {
 			logrus.Errorf("Failed to start streaming server: %v", err)
 		}
 	}()