Issue with Neuba config file about openbackdoor

[himanshubeniwal]

Same with configs/por_config.json;

File "demo_attack.py", line 61, in <module>
    main(config)
  File "demo_attack.py", line 42, in main
    backdoored_model = attacker.attack(victim, poison_dataset)
  File "/attackers/por_attacker.py", line 37, in attack
    victim_config = config["victim"]
TypeError: 'NoneType' object is not subscriptable

[lifan-yuan]

Thanks for pointing that out. We have fixed the bug.