nft: Header inclusion missing

Fixes compilation issues.

nft-shared.c: In function ‘nft_ipv46_rule_find’:
nft-shared.c:725:2: warning: implicit declaration of function ‘nft_rule_print_save’ [-Wimplicit-function-declaration]
nft-shared.c:725:32: error: ‘NFT_RULE_APPEND’ undeclared (first use in this function)
nft-shared.c:725:32: note: each undeclared identifier is reported only once for each function it appears in

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed