Rescue operation should honor the enable_instance_password conf value

[Phil Day]

Currently the rescue operation (enabled by the os-rescue) extension always returns a generated (or user supplied) password, although not all hypervisors support password injection.

For server create and rebuild operations the configuration option "enable_instance_password=False" can be used to suppress returning a meaningless and confusing password, and the rescue operation should also honor this setting

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/48196

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/48196
Committed: http://github.com/openstack/nova/commit/a19d72b0eacbc96236cac0e9306dae0de7c7cfc1
Submitter: Jenkins
Branch: master

commit a19d72b0eacbc96236cac0e9306dae0de7c7cfc1
Author: guohliu <email address hidden>
Date: Wed Sep 25 15:51:00 2013 +0800

    Fixes rescue doesn't honor enable password conf for v3

    The rescue api should honor enable_instance_password conf
    setting just like server creation and rebuild api does,
    enables this flag will returning the instance password from
    server API call rescue, If the hypervisor does not support
    password injection then the password returned will not be
    correct, this patch just fixes v3 rescue api, since change
    return value of v2 could potentially break apps which depend
    on this being returned.

    DocImpact
    Closes-bug #1213866

    Change-Id: Ie8422979940bbde8c5749fcd3d6c735e88f78c6a