Comment 2 for bug 1996182

Reviewed: https://review.opendev.org/c/starlingx/tools/+/863560
Committed: https://opendev.org/starlingx/tools/commit/cb140d1b8e4ee0c879b00c417a93ad701b51f9c5
Submitter: "Zuul (22348)"
Branch: master

commit cb140d1b8e4ee0c879b00c417a93ad701b51f9c5
Author: Takamasa Takenaka <email address hidden>
Date: Thu Nov 3 17:54:51 2022 -0300

    Make /opt/branding writable

    /opt/branding is used by end user to place their own
    theme for horizon. Branding files would be placed during
    installation or after installation but needs to be writable.

    Currently:
    /opt -> /var/rootdirs/opt
    /var/rootdirs/opt/branding -> /usr/rootdirs/opt/branding
    /dev/sda5 on /usr type ext4 (ro,noatime)
    So that, /opt/branding is read-only and user cannot place
    the branding file.

    This fix is creating new directory /var/branding and
    link to /opt/branding (by /usr/rootdirs/opt/branding)

    Closes-bug: 1996182

    Test Plan:
    PASS: Fresh install and confirm /opt/branding is writable.
    PASS: Copy branding tar file to /opt/branding before
          running ansible. Confirm branding tar file is extracted
          in /opt/branding when installation is finished.
    PASS: Copy branding tar file to /opt/branding after
          installation. Confirm branding tar file is extracted
          in /opt/branding after restarting horizon.
    PASS: Place branding file and upgrade. Confirm the branding
          file stays in /opt/branding and confirm the branding
          theme is applied in horizon.
    PASS: Run backup script and confirm branding tar file
          is included in the backup tar file.
    PASS: Run restore script and confirm branding tar file
          is restored in /opt/branding.

    Depends-On: https://review.opendev.org/c/starlingx/ansible-playbooks/+/864061

    Signed-off-by: Takamasa Takenaka <email address hidden>
    Change-Id: I292bace041ea9001d511647c5d04bc6bea99a0bd