install: Supports older dd in make-prep.sh (#878)
install: Supports older dd in make-prep.sh (#878)

Ubuntu-14.04.5 ships dd-8.21, it can be supported,
by testing progress args.

Also fail on errors in make-prep.sh

Change-Id: I60b93555d114f12215efdb0ce3a20a7adf54791c
Signed-off-by: Philippe Coval <ff46fec9739d31cce915aabcc3a7a2c00eee4d6c@osg.samsung.com>
mozilla-iot/gateway,mozilla-iot/gateway,moziot/gateway,mozilla-iot/gateway,mozilla-iot/gateway,moziot/gateway,mozilla-iot/gateway,moziot/gateway