Bright:Add kernel module to pxeboot image

• Needed to add pcnet32 to support my virtualbox cluster on the laptop!

[root@brighthead ~]# cmsh 
[brighthead]% softwareimage use default-image 
[brighthead->softwareimage[default-image]]% kernelmodules
[brighthead->softwareimage[default-image]->kernelmodules]% list
.. (loads of output)
[brighthead->softwareimage[default-image]->kernelmodules]% add pcnet32
[brighthead->softwareimage*[default-image*]->kernelmodules*[pcnet32*]]% commit 
[brighthead->softwareimage[default-image]->kernelmodules[pcnet32]]% 
Sun Oct 20 22:58:51 2013 [notice] brighthead: Initial ramdisk for image default-image is being generated