Add if judgment before receiving operations on daemonWaitCh

receive operations on a nil channel will always block, this lead containerd not started.

Signed-off-by: Shukui Yang <yangshukui@huawei.com>
Upstream-commit: a50d9c0765d9861d226b323ffe190c0c99c3ac17
Component: engine

components/engine/libcontainerd/remote_daemon.go

@@ -307,7 +307,9 @@ func (r *remote) monitorConnection(monitor *containerd.Client) {
 			<-time.After(100 * time.Millisecond)
 			system.KillProcess(r.daemonPid)
 		}
-		<-r.daemonWaitCh
+		if r.daemonWaitCh != nil {
+			<-r.daemonWaitCh
+		}
 
 		monitor.Close()
 		os.Remove(r.GRPC.Address)