Call older extlinux correctly.

Lubomir Rintel <lkundrak@v3.sk>

diff -up livecd-tools-013/tools/livecd-iso-to-disk.sh.extlinux-i livecd-tools-013/tools/livecd-iso-to-disk.sh
--- livecd-tools-013/tools/livecd-iso-to-disk.sh.extlinux-i	2008-10-27 12:29:08.000000000 +0100
+++ livecd-tools-013/tools/livecd-iso-to-disk.sh	2008-10-27 12:29:14.000000000 +0100
@@ -241,10 +241,14 @@ if [ "$USBFS" = "vfat" -o "$USBFS" = "ms
 	syslinux $USBDEV
     fi
 elif [ "$USBFS" = "ext2" -o "$USBFS" = "ext3" ]; then
+    # check if extlinux accepts -i option
+    extlinux -i -h 2>/dev/null
+    [ $? = 64 ] && I= || I=-i
+
     # extlinux expects the config to be named extlinux.conf
     # and has to be run with the file system mounted
     mv $USBMNT/$SYSLINUXPATH/isolinux.cfg $USBMNT/$SYSLINUXPATH/extlinux.conf
-    extlinux -i $USBMNT/syslinux
+    extlinux $I $USBMNT/$SYSLINUXPATH
     cleanup
 fi