Comment 2 for bug 1710295

Reviewed: https://review.openstack.org/493262
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=7f69969345ec027595d2530d646cc5fd820be65a
Submitter: Jenkins
Branch: master

commit 7f69969345ec027595d2530d646cc5fd820be65a
Author: John Griffith <email address hidden>
Date: Fri Aug 11 17:19:06 2017 -0600

    Make attachment_update set status to attaching

    The new attachment_update method in Cinder's API creates an attachment
    object and populates it with the provided connector info. In addition,
    we set the volumes status to in-use and update the attachment object
    status to "attached".

    This isn't really accurate though, because we don't know if the volume
    is actually attached (connected) by the consumer or not. Also a big
    side effect here is that currently all of our tests and automation
    use volume-status to determine if a volume is fully connected/ready
    for use and that everything went well. It's used as an ack in most
    cases.

    This change goes back to using multiple states to signify where a
    an attachment is in it's life-cycle:
    1. reserved
         We've created an empty attachment record but haven't done anything
         with it yet.
    2. attaching
         We provided a connector and set up the TGT so that everything is
         ready for a consumer to connect/use it.
    3. in-use
         An ACK back from the consumer letting us know that they connected
         it successfully and are doing their thing.

    Some consumers don't need or care about this last step, and we're going
    to provide a means to set it straight to attached/in-use, but for
    this bug we don't need to introduce that particular *feature*.

    Sadly, this requires a micro-version bump and a new API call to
    toggle the state from the API, pushing us to 3.44.

    closes-bug #1710295

    Change-Id: I57631d3deddb2d7cd244584e82206ee17fe2dd78