info_cache in Instance object can be None

[Chris Behrens]

Instance object ignores when joined info_cache returns None when it shouldn't. Also if instance.info_cache happens to be None, it'll not be de-serialized correctly.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47654

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47654
Committed: http://github.com/openstack/nova/commit/057534f2baf175b1deff0a34747107e21b41f6fd
Submitter: Jenkins
Branch: master

commit 057534f2baf175b1deff0a34747107e21b41f6fd
Author: Chris Behrens <email address hidden>
Date: Fri Sep 20 22:55:49 2013 +0000

    Instance object incorrectly handles None info_cache

    1) When getting records from the DB, it's possible for info_cache to be
    None, but this case was ignored.
    2) When de-serializing Instance with a None info_cache, a traceback
    would occur.

    Fixes bug 1228426

    Change-Id: I60e610aeafc9dea8d832adec10baaaecbae75215