argument of glance-cache-manage command is confusing

[Noboru Arai]

step to reproduce:
 *execute "glance-cache-manage" command as fallows
  -"glance-cache-manage queue-image 1fde5cfe-10be-4f38-86e7-9e54710d34f2 45f1c095-5b8c-4537-8dd3-a58f91d7b4e1"

result:
 *messeage is displayed as follows
  -Queue image 45f1c095-5b8c-4537-8dd3-a58f91d7b4e1 for caching? [y/N]

expected result:
   If the number of argument isn't one, commad fails.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/51110

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/51110
Committed: http://github.com/openstack/glance/commit/635ceac07969a700756e571ff5777993b59b9829
Submitter: Jenkins
Branch: master

commit 635ceac07969a700756e571ff5777993b59b9829
Author: Noboru Arai <email address hidden>
Date: Fri Oct 11 13:04:52 2013 +0900

    checking length of argument list in "glance-cache-image" command

    Currently, "image id" is got by "pop" method without checking length
    of argument list in "queue_image" method(glance/cmd/cache_manage.py)

    Consequently, only last element of argument list is used,
    other elements are ignored.
     ex)
      glance-cache-image queue-image <image-id1> <image-id2> <image-id3>
      -> <image-id3> is selected and queued.
         <image-id1>/<image-id2> is ignored.

    Because "glance-cache-image" command is user command(*),
    I think that elements which are ignored should not be existed
    and checking of length is essential.

    In order to check length, I replaced "try/except" statement with
    "if/else" statement.

    Also, I modified 2 methods at the same point.
     -delete_queued_image
     -delete_cached_image

     * http://docs.openstack.org/developer/glance/cache.html

    Change-Id: I5cff1f9b5fe8f718ca74f1c9f58dba469396dc8f
    Closes-Bug: #1236709