Comment 9 for bug 1684861

Reviewed: https://review.openstack.org/463364
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=593e7081148b2b15f5923a8d7c609ae71dcbdbb6
Submitter: Jenkins
Branch: stable/ocata

commit 593e7081148b2b15f5923a8d7c609ae71dcbdbb6
Author: Dan Smith <email address hidden>
Date: Thu Apr 20 09:12:45 2017 -0700

    Warn the user about orphaned extra records during keypair migration

    Operators who have manually deleted Instance records with FK constraints
    disabled may have orphaned InstanceExtra records which will prevent the
    keypair migration from running. Normally, this violation of the data
    model would be something that earns no sympathy. However, that solution
    was (incorrectly) offered up as a workaround in bug 1511466 and multiple
    deployments have broken their data as a result. Since the experience
    is a unhelpful error message and a blocked migration, this patch attempts
    to at least highlight the problem, even though it is on the operator to
    actually fix the problem.

    Change-Id: I0c8bf2c495a98c412eb93e19f832948a779bca11
    Related-Bug: #1684861
    (cherry picked from commit 2cee5bb4d14a5ad6a037857bd3624833317cd931)