fix weird bandit errors from circle ci

[ghbren]

Fixed weird bandit errors, like

raceback (most recent call last):
  File "/root/.local/lib/python3.7/site-packages/stevedore/_cache.py", line 159, in _get_data_for_path
    with open(filename, 'r') as f:
FileNotFoundError: [Errno 2] No such file or directory: '/root/.cache/python-entrypoints/c0ae7819d13f155229993453594e1ca065bae25b5a38401db52942abea84eca9'

These errors could only be reproduced from circle ci.

Solution described in PyCQA/bandit#730