xtables: add nf_tables vs. legacy postfix to version strings

-V now yields:
arptables vlibxtables.so.12 (nf_tables)
ebtables 1.6.2 (nf_tables)
ip6tables v1.6.2 (legacy)
ip6tables v1.6.2 (nf_tables)
ip6tables-restore v1.6.2 (nf_tables)
ip6tables-save v1.6.2 (nf_tables)
ip6tables-restore v1.6.2 (legacy)
ip6tables-restore-translate v1.6.2
ip6tables-save v1.6.2 (legacy)
ip6tables-translate v1.6.2 (nf_tables)
iptables v1.6.2 (legacy)
iptables v1.6.2 (nf_tables)
iptables-restore v1.6.2 (nf_tables)
iptables-save v1.6.2 (nf_tables)
iptables-restore v1.6.2 (legacy)
iptables-restore-translate v1.6.2
iptables-save v1.6.2 (legacy)
iptables-translate v1.6.2 (nf_tables)

This allows to see wheter "iptables" is using
old set/getsockopt or new nf_tables infrastructure.

Suggested-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
12 files changed