iptables-restore: resolve confusing policy error message

When iptables-restore (and ip6tables-restore) is unable to set a
chain's policy, it responds with a confusing message, e.g.:

iptables-restore v1.4.9: Can't set policy "PREROUTING" on "ACCEPT"
line 16: Bad built-in chain name

This is due to the chain and policy arguments being used in the wrong
order. The attached patch corrects this problem.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
diff --git a/ip6tables-restore.c b/ip6tables-restore.c
index 008566c..cea5f36 100644
--- a/ip6tables-restore.c
+++ b/ip6tables-restore.c
@@ -312,7 +312,7 @@
 					xtables_error(OTHER_PROBLEM,
 						"Can't set policy `%s'"
 						" on `%s' line %u: %s\n",
-						chain, policy, line,
+						policy, chain, line,
 						ip6tc_strerror(errno));
 			}