Hardcode provision-finished file path

A recent change removed the use of the cloudinit module, so write this
log to /var/lib/heat. Functional test paths updated as well.
(User data injection was removed, so that has been deleted as well.)

Change-Id: Ibcaf310a5e4ff9a9ed8b1065bdd411e1b95d4de5
Signed-off-by: Jeff Peeler <jpeeler@redhat.com>