Comment 6 for bug 1528201

Reviewed: https://review.openstack.org/266358
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=608b54137fb67512c07099089ea7e074176e12df
Submitter: Jenkins
Branch: stable/kilo

commit 608b54137fb67512c07099089ea7e074176e12df
Author: Kevin Benton <email address hidden>
Date: Thu Dec 24 00:54:06 2015 -0800

    Call _allocate_vr_id outside of transaction

    _allocate_vr_id is called from _set_vr_id, which was starting a
    transaction before calling it. This caused an error when the retry
    logic was triggered inside of _allocate_vr_id since it would
    encounter a DB exception and put the transaction into a bad state
    that couldn't be used on the retry.

    This patch just stops _set_vr_id from starting a transaction because
    it didn't serve a purpose. It also stops _allocate_vr_id from allowing
    subtransactions when it starts a transaction, since it's retry logic
    isn't compatible with them.

    Co-Authored-By: Ann Kamyshnikova <email address hidden>
    Closes-Bug: #1528201
    Change-Id: If7bcae39098f40f5ee9db78d3190bf9fdaf6438b
    (cherry picked from commit 18e2117e3df3c119f843aed669d0c6bae9243053)