Comment 2 for bug 1895042

Reviewed: https://review.opendev.org/750803
Committed: https://git.openstack.org/cgit/starlingx/utilities/commit/?id=6573fbe80c04e7cf85c46238c508aff1f2a04454
Submitter: Zuul
Branch: master

commit 6573fbe80c04e7cf85c46238c508aff1f2a04454
Author: Don Penney <email address hidden>
Date: Wed Sep 9 15:27:51 2020 -0400

    Fix missing log_error in update-iso.sh

    The update-iso.sh utility references an undefined log_error function.
    As a result, error messages are not properly reported, instead
    resulting in messages such as:
    stx-iso-utils.sh: line 53: log_error: command not found

    This error was introduced by code restructuring in a previous update:
    https://review.opendev.org/707673

    This update defines a log_error function for update-iso.sh that writes
    the message to stderr, as this is a user-run utility, so no need to
    log to syslog.

    Change-Id: Ifdc2a25c24cd86e61ccc12601a0bcbe6888ac349
    Closes-Bug: 1895042
    Signed-off-by: Don Penney <email address hidden>