iptables: warn when parameter limit is exceeded

While testing many match extensions in a single rule, I ran into this
error not warned about. Arguments were just ignored, causing
surprising "Need to specify an argument to --whatever" when the
argument was in fact given on the command line.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
diff --git a/iptables-restore.c b/iptables-restore.c
index bf80e78..519d480 100644
--- a/iptables-restore.c
+++ b/iptables-restore.c
@@ -103,8 +103,11 @@
 		newargv[newargc] = strdup(what);
 		newargc++;
 		return 1;
-	} else 
+	} else {
+		xtables_error(PARAMETER_PROBLEM,
+			"Parser cannot handle more arguments\n");
 		return 0;
+	}
 }
 
 static void free_argv(void) {