Some Debian pbuilders error out on some of the tests because
they cannot find kill to kill the test processes. Now if we
cannot find kill we skip those lot of tests.
Still need to work out why the S390 doesn't like test_sched
References: http://bugs.debian.org/725743
When ps is not available (like it may happen in a chroot), pgrep.exp and pkill.exp tests fail.
Use just build ps instead.
Signed-off-by: Gilles Espinasse <g.esp@free.fr>