Comment 2 for bug 1781391

Reviewed: https://review.openstack.org/582171
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=0ef4ed96d19a3576d67fdc9c1958610887d57ed4
Submitter: Zuul
Branch: master

commit 0ef4ed96d19a3576d67fdc9c1958610887d57ed4
Author: Chen <email address hidden>
Date: Thu Jul 12 20:33:14 2018 +0800

    fix cellv2 delete_host

    When trying to delete host that can be found in host_mappings
    but not in compute_nodes, current cellv2 delete_host will throw
    an exception but does not really handle it.

    This patch tries to handle this exception and allow the delete
    operation to continue since it shows the host has gone anyway.

    Change-Id: I99bd79fb45777edc0e33d846ba478b0a94a1191e
    Closes-Bug: #1781391