Enable v3 test_create_multiple_servers integrated test

[Christopher Yeoh]

Need to enable the integrated test_create_multiple_servers v3 version of the test
when the V3 multiple create extension merges

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/45804

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/45804
Committed: http://github.com/openstack/nova/commit/c883862751d3081bbc05eb4b40fc15abd4fa5b1b
Submitter: Jenkins
Branch: master

commit c883862751d3081bbc05eb4b40fc15abd4fa5b1b
Author: Chris Yeoh <email address hidden>
Date: Tue Sep 10 11:12:32 2013 +0930

    Enable test_create_multiple_servers test for V3 API

    Now that the multiple create extension has merged we can enable
    this test for the V3 API. Need to also override post_server
    for the test client for the V3 API as the data return when requesting
    a reservation id in the V3 API has changed

    Change-Id: I7f34f1e90b872c4679b5c54fe9e4b0f4420910ab
    Closes-Bug: #1206884