Comment 5 for bug 2042971

Reviewed: https://review.opendev.org/c/starlingx/config/+/900550
Committed: https://opendev.org/starlingx/config/commit/d9e12f6c455c4c2705848c026467a646f22db813
Submitter: "Zuul (22348)"
Branch: master

commit d9e12f6c455c4c2705848c026467a646f22db813
Author: Joshua Kraitberg <email address hidden>
Date: Thu Nov 9 12:46:50 2023 -0500

    Fix: Retain sysinv data during migration

    The migration code was deleting /opt/platform/<FROM_RELEASE>/sysinv,
    before it was migrated to /opt/platform/<TO_RELEASE>/sysinv.
    This caused the files inside like `sysinv.conf.default` to be lost
    during simplex upgrade.

    Originally, in legacy restore, `sysinv.conf.default` was
    individually restored after migration so the deletion
    had no impact.

    `sysinv.conf.default` is required on non-SX systems.
    This is used so that other hosts sysinv-agent can mount and
    have an initial sysinv.conf suitable for RPC to the controller.

    The loss of the file is not problematic on a SX system, but would
    prevent a later SX-to-DX migration.

    TEST PLAN
    PASS: Optimized upgrade AIO-SX, stx6 to stx8
    PASS: Optimized upgrade AIO-SX, stx7 to stx8

    Closes-bug: 2042971
    Signed-off-by: Joshua Kraitberg <email address hidden>
    Change-Id: I7a22e050f74785b99ea6b7758cf23d3419add1de