when launch instance boot from image(create a new volume) , if image size changed, device_size not change

[tinytmy]

When launch instance in instances panel.
 if use boot from image(create a new volume) source,
 if change the image, the device_size doesn't change,
although the selected flavor's disk and image's min_disk
is small than image's size.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/148848

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/148848
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=294f0cfd3e81d8b2aa08b7545546ddb2308cfe06
Submitter: Jenkins
Branch: master

commit 294f0cfd3e81d8b2aa08b7545546ddb2308cfe06
Author: tinytmy <email address hidden>
Date: Wed Jan 21 16:47:31 2015 +0800

    when launch instance image size changed, device_size not change

    When launch instance in instances panel.
    if use boot from image(create a new volume) source,
    if change the image, the device_size doesn't change,
    although the selected flavor's disk and image's min_disk
    is small than image's size.

    Change-Id: I3188b7ea6f87cd22a72b336a500fb5d781b82990
    Closes-bug:#1413112