avoid one unnecessary _get_power_state call

[jichenjc]

https://github.com/openstack/nova/blob/master/nova/compute/manager.py#L877

has _get_power_state in its function in
https://github.com/openstack/nova/blob/master/nova/compute/manager.py#L1042

then we call it again

https://github.com/openstack/nova/blob/master/nova/compute/manager.py#L878

actually there is no state change in _retry_reboot function
so we can reuse the state as variable and avoid mock in test

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/326431

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/326431
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=6211543493418509d5d1ace1a1ef55a3eebcd6b2
Submitter: Jenkins
Branch: master

commit 6211543493418509d5d1ace1a1ef55a3eebcd6b2
Author: jichenjc <email address hidden>
Date: Mon May 2 10:59:40 2016 +0800

    Avoid unnessary _get_power_state call

    the result of _get_power_state can be reused and no need to
    call it twice which don't have any state change.

    Change-Id: I3c495031d98b35734f37139ac1b1c3a4d25d0a8f
    Closes-Bug: 1589960

[Doug Hellmann (doug-hellmann)]

This issue was fixed in the openstack/nova 14.0.0.0b2 development milestone.