utils.runthis has unused argument and unused valiables

[Nachi Ueno]

prompt is not used.
https://github.com/openstack/nova/blob/stable/diablo/nova/utils.py#L274
rv, err are not used.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/3587

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/3587
Committed: http://github.com/openstack/nova/commit/d22b0210b0c4ef80b64531e6826985341e9af838
Submitter: Jenkins
Branch: master

commit d22b0210b0c4ef80b64531e6826985341e9af838
Author: Russell Bryant <email address hidden>
Date: Tue Jan 31 14:48:12 2012 -0500

    Remove utils.runthis().

    Fixes bug 884825. The bug was pointing out some unused variables
    noticed by pylint.

    utils.runthis() was only used in one place and doesn't really provide
    much value over utils.execute(), so just remove it.

    Change-Id: I3dcc34bd840a128418b58a8a66acb62adf3fc9cc