Comment 12 for bug 1892364

Reviewed: https://review.opendev.org/747845
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=a95ddf8ae853d0bd3b5dba89dc3e63a916bd52b2
Submitter: Zuul
Branch: stable/train

commit a95ddf8ae853d0bd3b5dba89dc3e63a916bd52b2
Author: Slawek Kaplonski <email address hidden>
Date: Thu Aug 20 22:39:04 2020 +0200

    Fix deletion of subnet_id from pd_subnets

    In the RouterInfo._process_internal_ports() method when it process
    old ports and port belongs to the subnet with CIDR assigned by
    Prefix Delegation it will try to remove subnet_id key from the
    pd_subnets dict.
    However it seems that in some case it may happen that such subnet_id key
    is not added to the pd_subnets dict and processing of ports fails.

    We shouldn't fail in such case, if there is no subnet_id key in this
    dict we should be good as we want to delete it simply. So this patch
    changes that to not raise KeyError in such case.

    Change-Id: I6e6d890c196716c0ef4bcc2922f1ec4c142a6e79
    Closes-Bug: #1892364
    (cherry picked from commit 13b894288e9354b9eb0833a635fe4a624bb068a9)