ansible bootstrap replay broken due to network range changes

[Joseph Richard]

Brief Description
-----------------
ansible bootstrap replay fails to remove controller-0 ip from loopback interface

https://bugs.launchpad.net/starlingx/+bug/1848376 fixed this in the initial install
This is also hit during ansible replay here
./playbookconfig/src/playbooks/roles/bootstrap/persist-config/tasks/shutdown_services.yml # Revert configuration to loopback interface

Incorrectly assumes that floating ip is the second ip, and then controller-0 ip is the third, causing an error when it tries removing controller-0 ip from loopback interface, as it doesn't exist

Severity
--------
Provide the severity of the defect.
<Major: System/Feature is usable but degraded>

Steps to Reproduce
------------------
attempt to replay ansible bootstrap

Expected Behavior
------------------
ansible bootstrap replay should pass

Actual Behavior
----------------
ansible bootstrap replay fails. will pass on subsequent apply

System Configuration
--------------------
reproduced on ipv6 multinode, but should be reproducible on any

[Ghada Khalil (gkhalil)]

stx.3.0 / high priority - this issue was introduced by recent code changes

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/691775

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/691775
Committed: https://git.openstack.org/cgit/starlingx/ansible-playbooks/commit/?id=e30ca938d77b69717cc0db081bbf3fe5636fc144
Submitter: Zuul
Branch: master

commit e30ca938d77b69717cc0db081bbf3fe5636fc144
Author: David Sullivan <email address hidden>
Date: Mon Oct 28 19:02:02 2019 -0400

    ansible bootstrap replay fails during lo ip removal

    https://bugs.launchpad.net/starlingx/+bug/1848376 missed updating the
    prev_management_start_address calculation. Making that calculation
    consistent with the fix for 1848376 addresses this issue.

    Change-Id: Iedcbd12d31c337cdd2448fd235645a87175907ee
    Closes-Bug: 1849887
    Signed-off-by: David Sullivan <email address hidden>