package.nfs-utils: drop extra empty line

Commit 12c0f68c (package/nfs-utils: bump version to 2.4.3) added an
extra empty line, causing check-package to whine:

    package/nfs-utils/nfs-utils.mk:27: consecutive empty lines

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>