vm_mode not updated during rebuild

[Johannes Erdfelt]

When rebuilding an instance to a new image with a different effective vm_mode, the instance isn't updated with the new vm_mode. This can cause problems (particular with the xenapi driver) when going from HVM to PV leading to an instance that cannot boot.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/82596

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/82596
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=ff6a3dc031d782d01607e28c8bd3fb5aa396bb16
Submitter: Jenkins
Branch: master

commit ff6a3dc031d782d01607e28c8bd3fb5aa396bb16
Author: Johannes Erdfelt <email address hidden>
Date: Mon Mar 24 13:08:22 2014 -0700

    Update vm_mode when rebuilding instance with new image

    Rebuilds can be made with a totally different image than what the instance
    was originally built with. If an image change also changes from HVM to PV
    mode, then vm_mode needs to updated on the instance as well. This also
    applies to os_type, architecture and auto_disk_config.

    Change-Id: I82f4580f0aab30dd3c1fa4cfc0ca76cc81d487e4
    Closes-bug: 1296818