use portable printf instead of echo -e, needed for MacOS X buildhost

echo -e is not a portable way to do this, better use printf.
Works with MacOS X.

Signed-off-by: Waldemar Brodkorb <mail@waldemar-brodkorb.de>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>