Comment 2 for bug 1475938

Reviewed: https://review.openstack.org/203384
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=80ee562dec3f397ea6c18a4ca3a1e69ab996341e
Submitter: Jenkins
Branch: master

commit 80ee562dec3f397ea6c18a4ca3a1e69ab996341e
Author: Eugene Nikanorov <email address hidden>
Date: Sun Jul 19 03:17:43 2015 +0400

    Fix _ensure_default_security_group logic

    In a case when first attempt to fetch default security group
    fails and attempt to add it fails too due to a concurrent insertion,
    later attempt to fetch the same default sg may fail due to
    REPEATABLE READ transaction isolation level.
    For this case RetryRequest should be issued to restart the
    whole transaction and be able to see default group.

    The patch also removes 'while True' logic as it's unsafe

    Closes-Bug: #1475938
    Change-Id: I20f65d3eae9421429aced1f4586cb6988ab577ff