Comment 13 for bug 1533013

Reviewed: https://review.openstack.org/460867
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=f15031f406b61f12e809e15d1b83bb24cdafd494
Submitter: Jenkins
Branch: stable/ocata

commit f15031f406b61f12e809e15d1b83bb24cdafd494
Author: Kevin Benton <email address hidden>
Date: Mon Mar 13 15:06:22 2017 -0700

    Check for None in _get_agent_fdb for agent

    get_agent_by_host can return None in the l2pop
    driver so we need to check for that case before
    we blindly try to decode configuration values on
    the result.

    There are a couple of cases that can lead to this.
    * The deployment can be misconfigured and is missing
      either a tunneling_ip option for the agent on a
      host or is missing an L2 agent with that host_id
      entirely.
    * Multiple mech drivers are in use and a port is being
      deleted from an agentless host.

    Related-Bug: #1533013
    Closes-Bug: #1672564
    Change-Id: I1e79f600172edad1e31e8231a0a6a2c55f46804c
    (cherry picked from commit c7fb24b3cb9cda1cc78e834a0153d219995ce97f)