Comment 7 for bug 1805164

Reviewed: https://review.openstack.org/620667
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=95cbc35b0bdae0de15569bc35fadbcf970da5b9e
Submitter: Zuul
Branch: master

commit 95cbc35b0bdae0de15569bc35fadbcf970da5b9e
Author: Matt Riedemann <email address hidden>
Date: Wed Nov 28 12:52:17 2018 -0500

    Provide a useful error message when trying to update non-compute services

    Starting in Pike, we disallowed trying to update (enable/disable/force down)
    non-nova-compute services because of multi-cell support using host mappings
    to lookup service records, and simply because disabling non-compute services
    doesn't do anything.

    However, before microversion 2.53, the error the user gets back is confusing:

      HTTP exception thrown: Host 'p024.domain.com' is not mapped to any cell

    This change provides a useful error message in this case and also changes
    the 404 response to a 400 response to align with the type of error and the
    behavior of the 2.53 microversion.

    Change-Id: I44f09aec60b0b18c458f9ba6d8b725db962e9cc7
    Closes-Bug: #1805164