[pkg-netfilter-team] Please give back nftables on stretch-backports

[Arturo Borrero Gonzalez]

Dear team,

due to a race in how packages were accepted from stretch-backports
NEW, buildd tried to build nftables without libxtables (from
src:iptables) which resulted in FTBFS.

Now that both packages are in stretch-backports, nftables should be build.

https://buildd.debian.org/status/package.php?p=nftables&suite=stretch-backports

thanks, best regards.