xenapi: image downloading code requires unnecessary instance argument

[Christopher Lefelhocz]

The downloading code in xenserver requires an instance argument. However in practice this argument is not used for debugging or any other purpose. Downloading in fact can occur without an instance being involved at all. We should remove this unused argument.

This is in preparation to separate out the download code and leverage it for precaching blueprint work. This should be treated as a bug on it's own as it's a code refactor/cleanup work.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/87356

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/87356
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=f9dfb5b25c087b5146e0c6a9956b2402aec6458f
Submitter: Jenkins
Branch: master

commit f9dfb5b25c087b5146e0c6a9956b2402aec6458f
Author: Christopher Lefelhocz <email address hidden>
Date: Sat Apr 12 03:52:14 2014 -0500

    XenAPI: Remove unneeded instance argument from image downloading

    The Xenapi image downloading code requires an instance argument
    when launching a VM. However, the downloading code doesn't
    need the instance information as it doesn't use it for
    any processing/debugging/loging. We can remove this
    argument safely.

    Change-Id: Id8b531b74e5f0e59638b608bff93fc89b66b889d
    Closes-bug: #1307662