The cleanup routines were being used to kill the rump process and to delete
the temporary image file. These are things automatically done by atf-run,
but it looks like this code was added here to workaround a previous bug in
the atf-run code.
Note that, in the existing form, the cleanup routines segfault (haven't
spent the time to track down why). atf-run does not care about this
(although it should), buy Kyua does.
As a side effect, this has a teeny-tiny performance speedup in the execution
of the tests including this file.
OKed by njoly@.