Comment 8 for bug 1868033

Reviewed: https://review.opendev.org/725931
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=e61d0025303b33ef00aa95ebd934f6121d320cbb
Submitter: Zuul
Branch: stable/ussuri

commit e61d0025303b33ef00aa95ebd934f6121d320cbb
Author: Dan Smith <email address hidden>
Date: Tue Apr 21 09:07:32 2020 -0700

    Remove stale nested backport from InstancePCIRequests

    Sometime in 2015, we removed the hard-coded obj_relationships mapping
    from parent objects which facilitated semi-automated child version
    backports. This was replaced by a manifest-of-versions mechanism
    where the client reports all the supported objects and versions
    during a backport request to conductor. The InstancePCIRequests object
    isn't technically an ObjectListBase, despite acting like one, and thus
    wasn't using the obj_relationships. Because of this, it was doing
    its own backporting of its child object, which was not removed in
    the culling of the static mechanism. Because we now no longer need to
    worry about sub-object backport chaining, when version 1.2 was added,
    no backport rule was added, and since the object does not call the
    base class' generic routine, proper backporting of the child object
    was not happening.

    All we need to do is remove the override to allow the base
    infrastructure to do the work.

    Change-Id: Id610a24c066707de5ddc0507e7ef26c421ba366c
    Closes-Bug: #1868033
    (cherry picked from commit d3ca7356860d64555eef6f5138501cb38f50ecc8)