SQLAlchemy Query can be used as an iterable to avoid creation of a list

[Roman Podoliaka]

A Query.all() call creates a list of a DB query results. We can actually use a Query instance as an iterable and thus avoid creation of a list if we just need to iterate over those values only once.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/27556

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/27556
Committed: http://github.com/openstack/quantum/commit/c7afedad00ea8a44770643c95714637ee8671000
Submitter: Jenkins
Branch: master

commit c7afedad00ea8a44770643c95714637ee8671000
Author: Roman Podolyaka <email address hidden>
Date: Thu Apr 25 16:15:59 2013 +0300

    Use Query instances as iterables when possible

    A Query.all() call creates a list of a DB query results.
    We can actually use a Query instance as an iterable and
    thus avoid creation of a list if we just need to iterate
    over those values only once.

    Fixes bug 1173133

    Change-Id: I06d8eaa9eaba4c71aa0c98000735cb9d83ea19a3