This commit adds `rescue` interface to `BaseDriver` and implements
it for `fake-hardware` hardware type. It adds configuration
parameters '[DEFAULT]/enabled_rescue_interfaces' and
'[DEFAULT]/default_rescue_interface'. The default value of
configuration parameter '[DEFAULT]/enabled_rescue_interfaces' is
`no-rescue`.
It adds new rescue states and a new 'rescue' field to the Node
object. It adds objects.node.Node._convert_to_version().
The method handles converting the new rescue_interface field
between different versions of the Node.
Partial-bug: #1526449
Co-Authored-By: Jay Faulkner <jay@jvf.cc>
Co-Authored-By: Josh Gachnang <josh@pcsforeducation.com>
Co-Authored-By: Jesse J. Cook <jesse.j.cook@member.fsf.org>
Co-Authored-By: Mario Villaplana <mario.villaplana@gmail.com>
Co-Authored-By: Aparna <aparnavtce@gmail.com>
Co-Authored-By: Shivanand Tendulker <stendulker@gmail.com>
Change-Id: I1534247bf207a20a7a58534988192aef392eaff2
433b1fd197