Delete in keypairs return 202, but it isn't sync call.

[Alex Xu]

delete keypairs will return 202, but look at the code it will access db directly, so it isn't sync. It returns 204 will better.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/56873

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/56873
Committed: http://github.com/openstack/nova/commit/33f98691d25d8019892eb81e881d01d1d09507a6
Submitter: Jenkins
Branch: master

commit 33f98691d25d8019892eb81e881d01d1d09507a6
Author: He Jie Xu <email address hidden>
Date: Mon Nov 18 15:28:10 2013 +0800

    Use 204 instead of 202 for delete of keypairs v3

    The delete of keypairs will access db directly. It isn't async call.
    So correct it to return 204.

    Closes-bug: 1252169
    DocImpact

    Change-Id: Ie36c16e1773fa7f61b22bd6735342c7308c7ba35