Comment 4 for bug 1753833

Reviewed: https://review.openstack.org/550967
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=8da6831e6375d013f0235a542b6b91580a43f61f
Submitter: Zuul
Branch: master

commit 8da6831e6375d013f0235a542b6b91580a43f61f
Author: Surya Seetharaman <email address hidden>
Date: Thu Mar 8 19:06:00 2018 +0100

    Make archive_deleted_rows handle a missing CONF.api_database.connection

    This change https://review.openstack.org/#/c/515034/ (added in queens)
    makes the archive_deleted_rows CLI remove instance mappings and request
    specs from the API database if there are instances archived from the
    main nova/cell database. However for this to work, the api database
    connection should be set in the config file. So in the case that the
    API database is not configured in the config file being used to run the
    CLI, we should gracefully handle the condition and and stop archiving thus
    prompting the user to set the api_db config and try the archival operation
    again. This patch fixes the graceful handling.

    Change-Id: I0c7b802a453aa423c7273ab724ce78eac0cfed4c
    Closes-Bug: #1753833