Fix InstanceIsLocked exception in server action

[huangtianhua]

We should catch the InstanceIsLocked exception in server actions which allow admins to operate.
Also V2 and V3 should be adjusted.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/58665

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/58665
Committed: http://github.com/openstack/nova/commit/1c6710a016b7dba18c4be799dd334565b0387448
Submitter: Jenkins
Branch: master

commit 1c6710a016b7dba18c4be799dd334565b0387448
Author: huangtianhua <email address hidden>
Date: Wed Nov 27 12:05:36 2013 +0800

    Catch InstanceIsLocked exception on server actions

    In v3, if the server is locked, a 409 error is raised, and the error msg
    is like "the server is locked". In v2 now, the 409 error is raised too. But the
    error msg is like "Instance is in an invalid state for \'pause(action name)\'".
    The error msg is inappropriate, two points:
    1. the state is valid for pause
    2. the message doesn't tell that the instance is locked

    The patch fixes the ploblem, and will do as v3. See the v3 commit:
    2c9fca6a3c916f3f594ddbb1a8ee8946b8ea3ac7

    Change-Id: I76572e37af686a4af35c31a3ea27f7070894b88a
    Closes-Bug: #1255386