cve-update-nvd2-native: log a little more

Add a note of what range we're fetching, and use bb.note() instead of
debug() as messages about retrying shouldn't really be considered debug
logging.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit b64a869b)
Signed-off-by: Steve Sakoman <steve@sakoman.com>