_default_block_device_names() throws unhandled exception for instances deleted during build

[Hans Lindgren]

During instance build, there is a call to _default_block_device_names() that contains a db call to update the instance. If the instance is deleted before this call it results in a InstanceNotFound exception that goes unhandled and ends up in the compute log. Since this is an expected error, it should be handled correctly.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/46354

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/46354
Committed: http://github.com/openstack/nova/commit/1967cee5abb71a23bccd440da9a27309a8d67081
Submitter: Jenkins
Branch: master

commit 1967cee5abb71a23bccd440da9a27309a8d67081
Author: Hans Lindgren <email address hidden>
Date: Thu Sep 12 22:38:40 2013 +0200

    Move call to _default_block_device_names() inside try block

    During instance builds, a call to _default_block_device_names() is
    made which contains a db call to update the instance. In case the
    instance is gone it will throw an unhandled InstanceNotFound exception.

    To properly handle this, move the call to _default_block_device_names()
    inside the existing try block next to it that handles this exception.

    Change-Id: I3503029f02669e6ae31441653096fa69cba76d45
    Closes-Bug: #1224677