Snapshot queries original image which could be gone

[Chris Behrens]

_get_minram_mindisk_params in compute api queries original image for properties, but the image could have been deleted, so we don't inherit min_ram/min_disk properties like we should.

There's other cases in the various compute driver implementations of 'snapshot' that also try to get the original image properties. All of these things should be converted to use the instance_system_metadata entries that are prefixed with 'image_'.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/11751

[Thierry Carrez (ttx)]

@Chris: still working on that ?

[John Garbutt (johngarbutt)]

https://review.openstack.org/#/c/43784

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/43784
Committed: http://github.com/openstack/nova/commit/4389f2292a0177c8eedc0a398ceb3c5535a9ef82
Submitter: Jenkins
Branch: master

commit 4389f2292a0177c8eedc0a398ceb3c5535a9ef82
Author: Xavier Queralt <email address hidden>
Date: Mon Aug 26 22:55:46 2013 +0200

    Avoid errors on some actions when image not usable

    Using the metadata saved on instance creation, we can now get all the
    image related metadata we need from the instance itself.

    This patch replace the logic for getting the image metadata on some
    actions that shouldn't fail when the image is not accessible (create
    an snapshot, resize, migrate, rescue an instance or attach an
    interface).

    Fixes bug 1039662

    Change-Id: Id8c2f13ca96908317d271a84fd685104b64f87e9