default ramdisk & kernel don't make sense

[Robert Collins]

I just spotted this in a review:
[pxe]
# Default kernel image ID used in deployment phase (string
#host=127.0.0.1 615 # value)
#deploy_kernel=<None>

# Default ramdisk image ID used in deployment phase (string
# value)
#deploy_ramdisk=<None>

These options don't make sense:
- kernel + ramdisk are arch specific, but pxe can deploy to many arches from one machine

They are also unlikely to be used by deployers:
- they require config changes + service restarts vs a single API call [per flavour, but flavors are small #'s]

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/70140

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/70140
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=12b524c076fd0d129cd7b855fce7fd565a2641fb
Submitter: Jenkins
Branch: master

commit 12b524c076fd0d129cd7b855fce7fd565a2641fb
Author: Ghe Rivero <email address hidden>
Date: Thu Jan 30 11:27:54 2014 +0100

    Remove deploy kernel and ramdisk global config

    This options are not very useful since ironic can deploy to
    multiple archs and any config change will require a service restart.

    Change-Id: I7282d86d0919d5057baff92010e4c1715126709e
    Closes-Bug: #1272741