set wireless extension to 0 by default

package/base-files/src/etc/network/if-pre-up.d/04-wireless

@@ -1,5 +1,4 @@
 #!/bin/sh 
-#set -x
 set -e 
 
 [ "${IFACE%%[0-9]*}" = "wlan" ] || exit 0
@@ -7,6 +6,7 @@ set -e
 [ "$IF_WIRELESS_SSID" ] || exit 1
 [ "$IF_WIRELESS_CHANNEL" ] || exit 1
 [ "$IF_WIRELESS_HWMODE" ] || IF_WIRELESS_HWMODE=g
+[ "$IF_WIRELESS_EXTENSION" ] || IF_WIRELESS_EXTENSION=0
 
 wpa=0
 wpa1=0