'uname -m' seems to be more general to get the machine's architecture
type.  Ubunbu 8.10 (and also all debian based distros?) does not have
arch(1).
Signed-off-by: Ryousei Takano <takano-ryousei@aist.go.jp>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>