Comment 16 for bug 1378904

Reviewed: https://review.openstack.org/635315
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=5dc1ed3c5cc20173eecd071b0804c469bdc9422f
Submitter: Zuul
Branch: master

commit 5dc1ed3c5cc20173eecd071b0804c469bdc9422f
Author: Matt Riedemann <email address hidden>
Date: Wed Feb 6 16:11:40 2019 -0500

    api-ref: warn about changing/unsetting AZ name with instances

    It is currently possible to rename or unset the availability_zone
    metadata value on a host aggregate which can adversely impact
    instances that were created in that specific AZ since later
    attempts to migrate or unshelve those instances will fail if the
    AZ with the original name no longer exists.

    This adds a warning to the API reference for updating the AZ
    name and also fixes a grammar typo in the 'metadata' response
    parameter description.

    Change-Id: Ie9d4a1ff1a23827490fe51350c11292c6efc4eb2
    Related-Bug: #1378904