setuptools >= 50 breaks pip installs

INFO:kolla.common.utils.openstack-base: ERROR: Command errored out with exit status 1:
INFO:kolla.common.utils.openstack-base: command: /var/lib/kolla/venv/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-75kolw3y/mysqlclient/setup.py'"'"'; __file__='"'"'/tmp/pip-install-75kolw3y/mysqlclient/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-c2m0gh_d
INFO:kolla.common.utils.openstack-base: cwd: /tmp/pip-install-75kolw3y/mysqlclient/
INFO:kolla.common.utils.openstack-base: Complete output (9 lines):
INFO:kolla.common.utils.openstack-base: Traceback (most recent call last):
INFO:kolla.common.utils.openstack-base: File "<string>", line 1, in <module>
INFO:kolla.common.utils.openstack-base: File "/var/lib/kolla/venv/lib/python3.6/site-packages/setuptools/__init__.py", line 5, in <module>
INFO:kolla.common.utils.openstack-base: import distutils.core
INFO:kolla.common.utils.openstack-base: File "/usr/local/lib/python3.6/dist-packages/_distutils_hack/__init__.py", line 83, in create_module
INFO:kolla.common.utils.openstack-base: return importlib.import_module('setuptools._distutils')
INFO:kolla.common.utils.openstack-base: File "/usr/lib/python3.6/importlib/__init__.py", line 126, in import_module
INFO:kolla.common.utils.openstack-base: return _bootstrap._gcd_import(name[level:], package, level)
INFO:kolla.common.utils.openstack-base: ModuleNotFoundError: No module named 'setuptools._distutils'
INFO:kolla.common.utils.openstack-base: ----------------------------------------

Related bug in setup tools repo: https://github.com/pypa/setuptools/issues/2353