libxtables: fix getaddrinfo return value usage

getaddrinfo return value on error can also be positive.

On Android they're positive, e.g.:

 android-ndk-r9d/platforms/android-19/arch-arm/usr/include/netdb.h
 147 #define EAI_NONAME       8      /* hostname nor servname provided, or not known */

And as a plus, it's not bad to conform to specs.

Signed-off-by: Domen Puncer Kugler <domen.puncer@samsung.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed