src: fix compile error due to _UNTIL renamed to _MODULUS in libnftnl

src: fix compile error due to _UNTIL renamed to _MODULUS in libnftnl

In the latest libnftnl, NFTNL_EXPR_NG_UNTIL was renamed to
NFTNL_EXPR_NG_MODULUS, so compile error happened:
  netlink_linearize.c: In function ‘netlink_gen_numgen’:
  netlink_linearize.c:184:26: error: ‘NFTNL_EXPR_NG_UNTIL’ undeclared
  (first use in this function)

Also update NFTA_NG_UNTIL to NFTA_NG_MODULUS.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>