Apply Nova rolling upgrade logic
Apply Nova rolling upgrade logic

This patchset apply Nova rolling upgrade logic [1]

[1] https://docs.openstack.org/nova/latest/user/upgrade.html

Change-Id: I2cc973896d08988c0db121673d357fd1d37e6e6c
Implements: blueprint apply-service-upgrade-procedure

openstack/kolla,rahulunair/kolla,rahulunair/kolla,stackforge/kolla,stackforge/kolla,stackforge/kolla,openstack/kolla