Leave an empty line between the header and package clause.

So it doesn't get into godoc output.

Change-Id: I743381322231dc20c68a27331ab53e2910f11947
Reviewed-on: http://review.couchbase.org/42864
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>