Image update help swaps disk and container format

[David Wittman]

Similar to image-create in #1051968, the image-update subcommand help has the metavars swapped for DISK_FORMAT and CONTAINER_FORMAT.

# glance help image-update
usage: glance image-update [--name <NAME>] [--disk-format <CONTAINER_FORMAT>]
                           [--container-format <DISK_FORMAT>]
...
  --disk-format <CONTAINER_FORMAT>
                        Disk format of image.
  --container-format <DISK_FORMAT>
                        Container format of image.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/20872

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/20872
Committed: http://github.com/openstack/python-glanceclient/commit/ed67c320144c74bd56f64e421ca069c6555771d6
Submitter: Jenkins
Branch: master

commit ed67c320144c74bd56f64e421ca069c6555771d6
Author: David Wittman <email address hidden>
Date: Wed Jan 30 22:04:11 2013 -0600

    Fix typo in image-update help page

    The image-update help page reversed the DISK_FORMAT
    and CONTAINER_FORMAT metavars.

    Fixes bug #1111054

    Change-Id: Iec8374782d00e8e9102141fb1e1c16d7f6ac136c