What is your objective with Boltztrap? Following recent tutorials, it looks like this qe2boltz.py and other python scripts are already out of date. I was able to successfuly follow this:
https://www.youtube.com/watch?v=lN_QLQmK7kQ
Check this video and the sequences. They are a introduction of newer versions of Boltztrap2. Also, take care with your python version. You are using python2 inside Aiida, aren't you? If you get newer version of Boltztrap2, python3 is needed.