Cells: metadata update calls don't get to the virt driver

[Andrew Laski]

When updating the metadata for an instance, the values should end up in xenstore for a guest to be able to query. This is related to https://bugs.launchpad.net/nova/+bug/1292181 but with instance objects metadata is now synced down to cells earlier than it used to be. This causes an issue with the metadata diff detection at the cell level so new keys are not pushed to the virt driver. This causes them to not be set in xenstore in the xenserver driver.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/80384

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/80384
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=c5e17f4dc2277ed422b060f860443d71a47fc440
Submitter: Jenkins
Branch: master

commit c5e17f4dc2277ed422b060f860443d71a47fc440
Author: Andrew Laski <email address hidden>
Date: Thu Mar 13 16:02:52 2014 -0400

    Don't sync [system_]metadata down to cells on instance.save()

    A cell should be authoritative for its metadata and system_metadata.
    rebuild relis on system_metadata not being updated until the cell
    updates it itself. update_instance_metadata relies on metadata not
    being updated so that it can calculate the diff properly.

    And before the objects conversion took place the compute.api.update()
    method that instance.save() replaced was not used for syncing metadata
    or system_metadata. So this change goes back to previous behaviour for
    cells.

    Change-Id: I339da9d1ff6d0e59f6a4ab68fd396bdfca7a224b
    Closes-bug: #1292181
    Closes-bug: #1292185