Comment 1 for bug 1757244

Reviewed: https://review.openstack.org/554394
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=cf9ea3fdb380e695aa2584106ee0c5b465b3055e
Submitter: Zuul
Branch: master

commit cf9ea3fdb380e695aa2584106ee0c5b465b3055e
Author: yenai <email address hidden>
Date: Tue Mar 20 09:58:31 2018 +0800

    Fix vhd image conversion regression

    A recent change introduced a regression: due to a wrong assignment,
    we're no longer passing qemu-img the right format when converting
    images to "vhd". Note that it expects the legacy "vpc" name.

    This change addresses this issue.

    Closes-Bug: #1757244

    Change-Id: If7a2e3470403b45eff69dcf69b67615bb982a4eb