Comment 4 for bug 1417239

Reviewed: https://review.openstack.org/152997
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=6f479a494e5f9270f6b4b7536d0bd16ad1b037f6
Submitter: Jenkins
Branch: stable/juno

commit 6f479a494e5f9270f6b4b7536d0bd16ad1b037f6
Author: Mathieu Gagné <email address hidden>
Date: Mon Feb 2 14:22:24 2015 -0500

    Don't create block device mappings in the API cell

    Otherwise 2 block_device_mapping entries will be created
    in the API cell:
    - the first one (created by the API cell) will have close to
      no information about the volume (device_name and volume_id are NULL)
    - the second one (bubbled up from the compute cell) will contain
      all the volume information

    The first entry confuses Nova when creating an image since
    it won't be able to find the associated volume (NULL) in Cinder.

    The compute cell should create it first and propagate it up
    to the API cell.

    Change-Id: I38edb953e73de6bc70a2e5950c68f457f83303e1
    Closes-bug: #1417239
    (cherry picked from commit 58633c4f085fc21be1e6439bb3d60d7492358d4a)