potential race condition with member role creation

[Guang Yee]

See

https://github.com/openstack/keystone/blob/master/keystone/assignment/core.py"https://github.com/openstack/keystone/blob/master/keystone/assignment/core.py#L256-L261

In a multi-worker environment, the second role creation call could result in conflict.

[Boris Bobrov (bbobrov)]

Could you please either describe the case when it happens or provide a test?

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/153654

[OpenStack Infra (hudson-openstack)]

Change abandoned by guang-yee (<email address hidden>) on branch: master
Review: https://review.openstack.org/153654
Reason: in favor of https://review.openstack.org/#/c/153656

[Lance Bragstad (lbragstad)]

Resolved by https://review.openstack.org/#/c/153656/3