Comment 13 for bug 1673483

Reviewed: https://review.openstack.org/472308
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=527834dea884d0663c1cf5f075c850e6f4a4eeaa
Submitter: Jenkins
Branch: stable/ocata

commit 527834dea884d0663c1cf5f075c850e6f4a4eeaa
Author: Matt Riedemann <email address hidden>
Date: Thu Mar 16 11:35:04 2017 -0400

    libvirt: add debug logging in detach_device_with_retry

    When we hit failures in this method it can be hard to
    sort out from a traceback what actually happened, and
    if we failed from the intial detach or if we failed
    during the retry loop.

    This patch adds some simple debug logging statements
    to help give context to what's going on when we need
    to debug a failure in this operation.

    Change-Id: I392192f139ced077664e54469eead0b0df9ebf4a
    Related-Bug: #1673483
    (cherry picked from commit 33d0b029f1927a455b6b00f41b4d83ed19a694ff)