It is an rudiment of zdtm.sh. Now we don't add ps to a test root
and we want to avoid forks in tests where it isn't supposed to be
called.

travis-ci: success for zdtm: don't call ps from tests
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>