delorean-repo:
replaced by tripleo-repos and other repo setup approaches
hosts:
heat hasn't manage hosts file for many releases
localboot:
replaced by diskimage-builder grub2, bootloader elements
ntp:
replaced by installing chrony package
os-net-config:
the package is installed by other elements, and the script is now
called from ansible
overcloud-dracut:
replaced by diskimage-builder dracut-regenerate element
overcloud-partition:
no image now uses this, overcloud-hardened-uefi-full uses
overcloud-partition-uefi
Change-Id: I990493b51d87a40140c1648f2b04c982ce959b1d
Steve Baker