Comment 2 for bug 1478987

Reviewed: https://review.openstack.org/206559
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=0eb3014195a3e300e6179296c2cfabfa4e785821
Submitter: Jenkins
Branch: master

commit 0eb3014195a3e300e6179296c2cfabfa4e785821
Author: Eric Harney <email address hidden>
Date: Tue Jul 28 10:19:07 2015 -0400

    Remove RetypeVD class, fix NFS driver retype

    retype() only exists in the deprecated VolumeDriver() class
    and not BaseVD. This means that drivers inheriting from *VD
    hit attribute errors when trying to call driver.retype().

    The thinking here is that RetypeVD isn't really necessary,
    since all drivers must implement some version of the retype
    method (even if it's a no-op with just a standard return code).

    Therefore, just rely on this being in the base driver class(es)
    rather than making it a separate abc class.

    Closes-Bug: #1478987
    Related-Bug: #1471807

    Change-Id: Ie0c6f23caf68080a05a10cc7ad245878a057fb02