No ONNX model graph displayed, unless there is other logs
Created by: jiayiliu
VisualDL renders an empty page if only onnx model is specified without additional logs
The same command:
visualdl -t 0.0.0.0 -p 8888 -m alexnet.onnx --logdir log
creates nothing if log dir is empty.
Wish this is a minor issue to be fixed.