netboot does not include the 'alx' driver in 12.04.3

Ubuntu version:
Description: Ubuntu 12.04.3 LTS
Release: 12.04

when building a netboot image (in initramfs.conf BOOT=nfs) the 'alx' module is not included.
This is a modules that is found here:
/lib/modules/3.8.0-34-generic/kernel/ubuntu/alx/alx.ko

and adds support for the Qualcomm Atheros QCA8171 Gigabit Ethernet adapter (among others)
The kernel does include the driver, but since it isn't under the 'net' directory, it isn't added to the initrd image, and net-booting is impossible

My fix was to create:
/usr/share/initramfs-tools/hooks/additional_net_modules
with the following contents:
----------
#!/bin/sh

set -e

PREREQ=""

prereqs () {
        echo "${PREREQ}"
}

case "${1}" in
        prereqs)
                prereqs
                exit 0
                ;;
esac

. /usr/share/initramfs-tools/hook-functions

manual_add_modules alx

exit 0
----------

I then rebuild the initramfs image via:
update-initramfs -u

It is probably rare that someone has both this hardware and is netbooting, but this took me a while to figure out, and would be a nice to have fix for 12.04.4