[RFE] Add validate_rescue() method for boot interface

[Shivanand Tendulker]

All the rescue interface related properties gets used in booting up the ramdisk. They should be logically validated through the boot interface. Add a validate_rescue() method for boot interface to perform the same.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/540954

[Ruby Loo (rloo)]

This looks like clean up of the rescue feature. I'm assuming this new method wasn't mentioned in the rescue spec and we've landed the rescue code. I tagged this as an RFE because it modifies the Interface API. Since Dmitry has started to review the patch and I'm good with this, I'm approving it :)

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/540954
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=1c162058e3f20c89716290360b3c54024429ee64
Submitter: Zuul
Branch: master

commit 1c162058e3f20c89716290360b3c54024429ee64
Author: Shivanand Tendulker <email address hidden>
Date: Mon Feb 5 12:28:49 2018 -0500

    Add validate_rescue() method to boot interface

    Adds validate_rescue() method to boot interface to validate node's
    boot properties related to rescue operation. This method is called
    by the validate() method of rescue interface.

    Closes-Bug: #1747467
    Change-Id: Ib68d49a9cdb2ae4a5d43b90716c0a0c1166398c0

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/ironic 11.0.0 release.