Comment 3 for bug 1525452

Reviewed: https://review.openstack.org/256966
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=3f3a8f11571a71770f08bc2ef48562300b44d9f7
Submitter: Jenkins
Branch: master

commit 3f3a8f11571a71770f08bc2ef48562300b44d9f7
Author: John Griffith <email address hidden>
Date: Sat Dec 12 18:32:57 2015 +0000

    Fix invalid cache image-volume creation

    During the volume ref creation in clone_image_volume
    we were including a _name_id attribute which is invalid
    in the base olso object. The result is silent failure
    for a key error. Note that the comments for the column
    in the db specifcally state "do not call directly".
    The variable is also denoted as private by the _ prefix.

    Fix this by just popping the "_name_id' attribute.

    In addition there were a number of things that needed
    some cleanup:
    1. Don't iterate over list of tuples to get K/V for dict
       Just use Dict(xxxx)
    2. Don't use delete dict.key
       This isn't safe, because if the key DNE you'll get a key exception
       Instead use pop which is safe if key DNE
    3. Add an error message when this fails, because currently the logs
       don't give an operation a chance of knowing it failed, let alone
       an opportunity to debug it

    Finally the cache volume creation is still calling the db
    directly and doing a resource create as opposed to
    using the new volume object create handler. I went ahead
    and converted this to use objects, however that resulted in
    breaking two of the volume-->image unit tests that use cinder
    as a glance backend.

    I've opened bug 1525773 for those issues and added a skip
    to the tests in question.

    Change-Id: Ieda40c1111d4d4d69488944eb332962eb9658266
    Closes-Bug: #1525452