Use the same variable for TRIPLEO_CLEANUPs.

When I added test environment support I used a different variable
name than we already used in devtest_setup.sh. This creates some
confusion, so renaming it to match.

Change-Id: Iad24a5a8100e5de8ab0016562cf1feebe3337bf2
Merge "Use the same variable for TRIPLEO_CLEANUPs."