Use openstack-tox-py36
Replace legacy tox job with new v3 python36 job.
Depends-On:
- legacy-swiftclient-dsvm-functional
- legacy-swiftclient-dsvm-functional-identity-v3-only:
voting: false
- - legacy-python-swiftclient-python36-fedora-26:
+ - openstack-tox-py36:
voting: false
gate:
queue: integrated
