validate_networks does unnecessary querying to neutron in some cases

[Aaron Rosen]

This patch optimizes validate_networks so that it only queries neutron
when needed. Previously, this method would perform an additional net_list,
list_ports, and show_quota regardless if a request contains only
port_ids. If a request only contains port ids we do not need to check neutron
for quota as these ports are already allocated.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/80055

[Openstack Gerrit (openstack-gerrit)]

Reviewed: https://review.openstack.org/80055
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=6e5f6041a38ddb0b2643dff66d264f3594f1a875
Submitter: Jenkins
Branch: master

commit 6e5f6041a38ddb0b2643dff66d264f3594f1a875
Author: Aaron Rosen <email address hidden>
Date: Wed Mar 12 12:05:15 2014 -0700

    Optimize validate_networks to query neutron only when needed

    This patch optimizes validate_networks so that it only queries neutron
    when needed. Previously, this method would perform an additional net_list,
    list_ports, and show_quota regardless if a request contains only
    port_ids. If a request only contains port ids we do not need to check neutron
    for quota as these ports are already allocated.

    Change-Id: Ia7abc7d95b663f165fc95385dda3bab13b7a43e6
    Closes-bug: #1291565