Update help for glance member-update v2 api

[Yamini Sardana]

The output for glance --os-image-api-version 2 help member-update should display the options available for MEMBER STATUS field (Accepted, Rejected, Pending)

At the moment it does not display the available options.

[Yamini Sardana (yamini-sardana)]

Fix proposed to branch: master
Review: https://review.openstack.org/156481/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/156481
Committed: https://git.openstack.org/cgit/openstack/python-glanceclient/commit/?id=db5d72947c6a00cbe9cc62af3af157d79ca25b8e
Submitter: Jenkins
Branch: master

commit db5d72947c6a00cbe9cc62af3af157d79ca25b8e
Author: Yamini Sardana <email address hidden>
Date: Tue Feb 17 11:39:13 2015 +0530

    Updated help for v2 member-update api

    help message for v2 glance member-update api
    now displays the Valid Values of member status
    variable.

    The valid values are: pending, accepted, rejected

    Change-Id: Ibe6f55c933668451b407ed9a19c520c3fbf1912a
    Closes-bug: #1420707