Fix typo with tripleo-cd systemd unit
Fix typo with tripleo-cd systemd unit

This apparently isn't used yet, so we haven't hit  this pretty obvious
typo.

Thanks to Derek for also pointing the incorrect ExecStart path.

Change-Id: Ic4735d52f22377a7a0bdec956cb2d235b714dfde

openstack/tripleo-image-elements,rdo-management/tripleo-image-elements,radez/tripleo-image-elements,rdo-management/tripleo-image-elements,openstack/tripleo-image-elements,radez/tripleo-image-elements