xtables: remove bogus comment regarding rule replacement

We support rule replacement since quite some time, remove it.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/iptables/xtables.c b/iptables/xtables.c
index 41a7f71..7a6509a 100644
--- a/iptables/xtables.c
+++ b/iptables/xtables.c
@@ -1178,7 +1178,6 @@
 				   args.s, args.d, cs.options&OPT_VERBOSE, h);
 		break;
 	case CMD_REPLACE:
-		/* FIXME replace at rulenum */
 		ret = replace_entry(chain, *table, &cs, rulenum - 1,
 				    h->family, args.s, args.d,
 				    cs.options&OPT_VERBOSE, h);