UBUNTU: SAUCE: install nfs-kernel-server in preseeds

If we use an unattended install to generate the qcow2 image, we need
to have nfs-kernel-server installed in order to use nfs.
UBUNTU: SAUCE: Add ubuntu LTS ini files.

Add ini files for ubuntu 12.04/14.04 32/64 bit.

Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>