Use virtio driver for fuel-master NIC

Use virtio driver for fuel-master NIC

Using e1000 driver on fuel master may lead to temporarily loss of
communication [1]. We can use two approaches here:

  * use virtio driver
  * install e1000-kmod package

virtio driver should be sufficient for our purposes, we don't use
bonding on fuel master.

e1000-kmod package is available on fuel master and provide e1000 kernel
module which does not introduce additional problems. This package is not
installed by default but for this purpose MASTER_NODE_EXTRA_PACKAGES
cmdline option can be set during fuel master installation.

[1]
http://docs.openstack.org/developer/fuel-docs/userdocs/release-notes/fuel_known_issues.html

Change-Id: I3fc1fed5f0b9c780cd9174205a3c31dae92a180e
Signed-off-by: Michal Skalski <mskalski@mirantis.com>