Replace single pattern case-blocks with simpler code.

OK halex@

src/etc/rc

@@ -1,4 +1,4 @@
-#	$OpenBSD: rc,v 1.473 2015/12/06 13:51:41 rpe Exp $
+#	$OpenBSD: rc,v 1.474 2015/12/29 19:41:24 rpe Exp $
 
 # System startup script run by init on autoboot or after single-user.
 # Output and error are redirected to console by init, and the console is the
@@ -238,9 +238,7 @@ if [[ $1 == shutdown ]]; then
 
 	# Bring carp interfaces down gracefully.
 	ifconfig | while read _if _junk; do
-		case $_if in
-		carp+([0-9]):) ifconfig ${_if%:} down ;;
-		esac
+		[[ $_if == carp+([0-9]): ]] && ifconfig ${_if%:} down
 	done
 
 	exit 0
@@ -293,14 +291,12 @@ if [[ $pf != NO ]]; then
 	fi
 	RULES="$RULES\npass in proto carp keep state (no-sync)"
 	RULES="$RULES\npass out proto carp !received-on any keep state (no-sync)"
-	case $(sysctl vfs.mounts.nfs 2>/dev/null) in
-	*[1-9]*)
+	if [[ $(sysctl vfs.mounts.nfs 2>/dev/null) == *[1-9]* ]]; then
 		# Don't kill NFS.
 		RULES="set reassemble yes no-df\n$RULES"
 		RULES="$RULES\npass in proto { tcp, udp } from any port { sunrpc, nfsd } to any"
 		RULES="$RULES\npass out proto { tcp, udp } from any to any port { sunrpc, nfsd } !received-on any"
-		;;
-	esac
+	fi
 	print -- "$RULES" | pfctl -f -
 	pfctl -e
 fi