configurehood: Leverage -H option for batctl

Since batctl can suppress headers, we do not have to count lines.

Cosmetical change.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Fabian Bläse <fabian@blaese.de>
Reviewed-by: Robert Langhammer <rlanghammer@web.de>