- specifically match carp+([0-9]):, not just carp*:. avoids spurious

attempts to "ifconfig carp down" noticed by david@.
- use non-descriptive variables names rather than $if/$junk to encourage
people reading the code to think what it's doing; many of the output lines
are not interface names.
ok david@

src/etc/rc

@@ -1,4 +1,4 @@
-#	$OpenBSD: rc,v 1.330 2009/08/05 02:06:21 deraadt Exp $
+#	$OpenBSD: rc,v 1.331 2009/08/07 22:27:47 sthen Exp $
 
 # System startup script run by init on autoboot
 # or after single-user.
@@ -166,9 +166,9 @@ if [ X"$1" = X"shutdown" ]; then
 		echo /etc/rc.shutdown complete.
 
 		# bring carp interfaces down gracefully
-		ifconfig | while read if junk; do
-			case $if in
-			carp*:) ifconfig ${if%:} down ;;
+		ifconfig | while read a b; do
+			case $a in
+			carp+([0-9]):) ifconfig ${a%:} down ;;
 			esac
 		done