xenapi tries to shutdown rescue instance even if it's already shutdown

[Johannes Erdfelt]

It will end up with an error like this:

['VM_BAD_POWER_STATE', 'OpaqueRef:5f9021b0-dc99-9b3a-c0b6-e820158d7c0b', 'paused, suspended, running', 'halted']

The code should check the state first and only shut it down if it isn't already halted.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/5641

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/5641
Committed: http://github.com/openstack/nova/commit/4944a612e0926cfe542e0cb146cc9fabf70256f6
Submitter: Jenkins
Branch: master

commit 4944a612e0926cfe542e0cb146cc9fabf70256f6
Author: Johannes Erdfelt <email address hidden>
Date: Wed Mar 21 18:59:57 2012 +0000

    Only shutdown rescue instance if it's not already shutdown

    Fixes bug 961507

    Change-Id: Ib48d6ea3ad7c89e922cde8e0c0952d1bee2ca7bf