Comment 3 for bug 1926512

Reviewed: https://review.opendev.org/c/starlingx/config/+/788733
Committed: https://opendev.org/starlingx/config/commit/67c214a4e4ac234ceab33d1514f550eea41ae928
Submitter: "Zuul (22348)"
Branch: master

commit 67c214a4e4ac234ceab33d1514f550eea41ae928
Author: John Kung <email address hidden>
Date: Thu Apr 29 07:55:55 2021 -0500

    Clear host config_target on upgrade migration

    The host config_target is taken as a snapshot on the upgrade-start.
    This can lead to config out of date condition if the N controller
    issues subsequent config requests. This is more likely in duplex
    controllers, however, for consistency the config_target is reset
    to track when the N+1 controller is active.

    Clear the config target of all hosts on upgrade migration. The N+1
    controller will resume tracking the config by generating config_target
    when configuration is issued.

    Condition for upgrade activation-complete is updated to account
    for potential None config_target.

    Verified upgrade complete on AIO-SX and Duplex systems.

    Change-Id: I4dd44e6548a45d32ab6a0b6735a04d624da7caad
    Closes-Bug: 1926512
    Signed-off-by: John Kung <email address hidden>