bdm dict item read as attribute in snapshot_volume_backed

[Hans Lindgren]

Stumbled upon an error similar to the one found in
https://review.openstack.org/#/c/23354/ where a dbm dict
item is tried to be read as an attribute.

if bdm.no_device:

should be replaced with

if bdm['no_device']:

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/23376
Committed: http://github.com/openstack/nova/commit/4a2c57684c18f90f23263156f952561154751e09
Submitter: Jenkins
Branch: master

commit 4a2c57684c18f90f23263156f952561154751e09
Author: Hans Lindgren <email address hidden>
Date: Sun Mar 3 16:19:08 2013 +0100

    Fix an error in compute api snapshot_volume_backed bdm code

    Stumbled upon an error similar to the one found in
    https://review.openstack.org/#/c/23354/ where a dbm dict
    item is tried to be read as an attribute.

    Looked at the next couple of lines and discovered more
    cases of this error.

    Updates to some api tests that contain faulty fakes that
    hide this error adds some coverage for this error. Rebased
    this patch on the above mentioned review to be able to
    change the tests, since the code path is the same and they
    now hit both of these errors.

    Resolves bug 1142734.

    Change-Id: Ie639cd483334b6222085a139159da47ce6fa3671