Lack of API schema definition for different cell filter

[Ken'ichi Ohmichi]

For using the different cell filter, the API parameter different_cell needs to be passed to the corresponding filter.
but v2.1 API validation denies it and it didn't work at all.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/220893

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/220893
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=029ad7e1234c1fcd6913ea7e056ade74fe3cef5b
Submitter: Jenkins
Branch: master

commit 029ad7e1234c1fcd6913ea7e056ade74fe3cef5b
Author: Ken'ichi Ohmichi <email address hidden>
Date: Tue Sep 8 02:48:30 2015 +0000

    Add API schema for different_cell filter

    For using the different cell filter, the API parameter different_cell
    needs to be passed to the corresponding filter. However v2.1 API
    validation denies it because there is not API parameter definition
    and it didn't work at all.
    This patch adds the API schema.

    Change-Id: Ic61b9a18722b7701b09e71f3f3a547ad9e6363c2
    Closes-Bug: #1492925