Fix daemon panic on restoring containers

Signed-off-by: Lei Jitang <leijitang@huawei.com>
(cherry picked from commit c75de8e33cc0db5236eef6146f2de06533b46aa8)
Signed-off-by: Tibor Vass <tibor@docker.com>

libcontainerd/client_linux.go

@@ -563,6 +563,8 @@ func (clnt *client) Restore(containerID string, options ...CreateOption) error {
 		clnt.remote.Lock()
 		return nil
 	}
+	// relock because of the defer
+	clnt.remote.Lock()
 
 	clnt.deleteContainer(containerID)