xenapi: Added iPXE ISO boot support

[OpenStack Infra]

https://review.openstack.org/38650
commit 2459d0fb2af37d5d54c9608e4cbcb52bc12bf0ef
Author: Josh Kearney <email address hidden>
Date: Thu Jul 18 13:57:54 2013 -0500

    xenapi: Added iPXE ISO boot support

    This gives customers (of service-providers running XenAPI) a means to roll
    their own image.

    The service-provider supplies an ISO with iPXE support rolled into it and then
    the customer can choose that image, boot to an OS of their choosing, then the
    customize the image in anyway they want.

    Two virt-layer modifications were needed. The first was adding configurations
    for the iPXE ISO feature (network to use, boot menu, mkisofs_cmd). The second
    was the ability to inject networking info into the ISO after it was
    downloaded.

    This was accomplished via a new post-image-download hook (fixup_disks) and a
    new dom0 plugin that knows how to mount an ISO, copy it, inject networking,
    rebundle it, and place the modified version back into the SR.

    DocImpact

    Change-Id: I33acf9dfdff0a5ed9797723a142bc451348e8549

[Tom Fifield (fifieldt)]

This is currently blocked by the blueprint: redocument-xen

[Lana (loquacity)]

Closed as out of date.