This patch implements the part that reads the specified boot_option in
the node.instance_info['capabilities'] that have been passed to Ironic by
the Nova Ironic Driver and pass that information to the deploy ramdisk
by adding it to the kernel cmdline in the PXE configuration file that
will be generated to that node.
This patch also makes sure that we clean the PXE configuration files for
the node marked to local boot after it's deployed, so that any attempt
to boot it from the network will not work.
This patch only apply to the pxe_* drivers, because the blueprint is
about adding local boot support for deployments that uses partition
images. The agent driver right now supports full disk images only.
Implements: blueprint local-boot-support-with-partition-images
Change-Id: Ide08e2b41dcf74c69dfbce242112da701fa15187
fb9520b701