devstack: for openSUSE Leap 15.0 start using python3
devstack: for openSUSE Leap 15.0 start using python3

Devstack will automatically use python2 for packages which
dont support python3*, eg: swift
lets do this ! it is time already.

aspiers/automation,aspiers/automation,aspiers/automation,gosipyan/automation,gosipyan/automation,SUSE-Cloud/automation,SUSE-Cloud/automation,gosipyan/automation,gosipyan/automation,aspiers/automation,SUSE-Cloud/automation,SUSE-Cloud/automation