fail to get test starting with droidbot

[joykou90]

problem encountered:

• works well when only using droidbot
• kept showing following AttributeError while using with humanoid and get stuck in the launch screen

steps:

1. start humanoid service: $ python3 agent.py -c config.json
2. after seeing === Humanoid RPC service ready at localhost:50405 === along with a lot warnings, $cd droidbot
3. $droidbot -a ~/apps/makor.apk -o ~/output -humanoid localhost:50405
4. AttributeError: 'NoneType' object has no attribute 'state_str'

test env:

• ubuntu 16.04 phisical machine
• test with an apk of Android 4.4.2, API 19, Nexus 5 emulator
• tensorflow v1.15 no GPU support
• python 3.5