grizzly: allow cross-availability zone attaching of volumes

[Tom Fifield]

https://review.openstack.org/21672 introduces a new configuration option to nova:

   54 cfg.BoolOpt('cinder_cross_az_attach',
   55 default=True,
   56 help='Allow attach between instance and volume in different '
   57 'availability zones.'),

    Make check_attach() optionally check if the volume and instance
    are in the same availability zone and if cross AZ attach
    is configured as not allowed report error.

    This does not change the current default behaviour.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/22170

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/22170
Committed: http://github.com/openstack/openstack-manuals/commit/2e59e5a8373ded6565f62fefaf39862006449c76
Submitter: Jenkins
Branch: master

commit 2e59e5a8373ded6565f62fefaf39862006449c76
Author: Tom Fifield <email address hidden>
Date: Mon Feb 18 16:16:11 2013 +1100

    Add cinder_cross_az_attach option

    fixes bug 1128546

    This patch adds the cinder_cross_az_attach option to toggle
    whether volume attachments are allowed between zones, which was
    added in Grizzly.

    Given the current state of cinder and availability zone documentation
    this patch might be a little worthless. However, at least it will
    allow understanding of the default behaviour.

    Fix minor typo and spelling error.

    Change-Id: Idff7a59a726d70e229fcb18d98deb5b38ce649fc