add ssh console to preseed and ubuntu with keys

[Matthew Mosesohn]

CentOS:
add sshd=1 to kernel options
add sshpw --username root --iscrypted $HASH #We must set it to something or else it will allow empty password

add %pre snippet:
mkdir /root/.ssh
chmod 700 /root/.ssh
curl SSH pubkey from admin node to /root/.ssh/authorized_keys2
chmod 600 /root/.ssh/authorized_keys2

Ubuntu:
d-i anna/choose_modules string network-console
d-i network-console/authorized_keys_url string http://fuel-master/sshkey.pub

This will greatly enhance our ability to stop/reset a deployment

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/72959

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/72959
Committed: https://git.openstack.org/cgit/stackforge/fuel-library/commit/?id=a61eeea68ad844797fcbd361b4a1fdeb17a82e34
Submitter: Jenkins
Branch: master

commit a61eeea68ad844797fcbd361b4a1fdeb17a82e34
Author: Aleksandr Didenko <email address hidden>
Date: Wed Feb 12 16:55:52 2014 +0200

    Add ssh console to anaconda and preseed

    Adds ssh console to CentOS and Ubuntu nodes during provisioning.
    SSH is accessible from Fuel master node via Admin network IPs with
    Fuel root RSA ssh key. Password authentication is not available.

    Anaconda/Debian-installer stop commands have been removed from the
    login profiles. Orchestrator should execute something like the
    following in order to pause provisioning on the node:

    - CentOS/RH: "killall -STOP anaconda"
    - Ubuntu: "killall -STOP debootstrap dpkg"

    Change-Id: Ic34b7e6f154c084bd03c29cc5ce1d22edfc165ad
    Closes-Bug: #1277447