Restart os-collect-config automatically from undercloud-metadata.

os-collect-config can actually get hung trying to connect to nova_bm database
from the compute node because it tries to reconnect infinitely.  Therefore, we
need to restart the service after updating the static json configuration with
undercloud-metadata.
Set hostnames for control and leaf in the kickstart files.
Enable sshd service in the kickstart file used to install the live image to
disk.
README updates.