create with a soft fail (create or show) for keystone operations

[Steve Martinelli]

as discussed at the latest summit, we should extend the shell to soft fail (create or show), where it attempts to create a resource, and show the resource if it's already created. probably most helpful for keystone resources.

[Steve Martinelli (stevemar)]

note, we can do this with (set or create), where if the user tries to update a resource that does not exist, it is created instead.

[Dean Troyer (dtroyer)]

As of this writing, the following reviews have merged implementing --or-show: https://review.openstack.org/133197 (Identity v2 user)

The following reviews are in progress: https://review.openstack.org/#/c/133996/ (Identity v2 role, project), https://review.openstack.org/#/c/134452/ (Identity v3 role, project, domain, user, group)

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/134452
Committed: https://git.openstack.org/cgit/openstack/python-openstackclient/commit/?id=79653afa7b7f4c3795f6fe3c972628729cb51b4d
Submitter: Jenkins
Branch: master

commit 79653afa7b7f4c3795f6fe3c972628729cb51b4d
Author: Steve Martinelli <email address hidden>
Date: Fri Nov 14 01:59:14 2014 -0500

    Add --or-show support for v3 identity resources

    Add --or-show for the following:
      * v3 roles
      * v3 projects
      * v3 domains
      * v3 users
      * v3 groups

    Closes-Bug: #1390389
    Change-Id: Id4ef043e5fda6be49a515eb3fe138c813c393ec9