Fixed prepare.sh to create cvp.ubuntu.spt image

The script did not create the cvp.ubuntu.spt image and
was having the error "[Errno 2] No such file or directory:
'ubuntuspt'".
The fix is using downloaded cvp.ubuntu.1604 image file
to create an spt image.

Related-PROD: PROD-36128
Change-Id: I172f5ebc9155913e5ffe8af2ccf7d1808d206763
1 file changed
tree: c802b02738faf53dd3dacbc4a2a98d5897a063df
  1. k8s/
  2. rally/
  3. scripts/
  4. tempest/
  5. wally/
  6. cleanup.sh
  7. configure.sh
  8. Dockerfile