Code review comment for lp:~ltrager/maas/lp1587896

The architecture fix was actually pointed out by Blake. archdetect outputs as amd64/efi on UEFI machines, I didn't notice this as I've been testing with libvirt which emulates a traditional BIOS. This modifies refreshes to mimic commissioning and only take the architecture part from archdetect, not the subarch.

http://bazaar.launchpad.net/~maas-committers/maas/trunk/view/head:/etc/maas/templates/commissioning-user-data/snippets/maas_enlist.sh#L72