sdk.py: error out when moving file fails

Instead of printing an error message and continuing, we should just
error out when moving file fails.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 12aecd9d)
Signed-off-by: Steve Sakoman <steve@sakoman.com>