Resolve conflicting mac address in resize

This patch fixes bug 1161226 and mac address conflicts when migrating or
resizing an instance using the PowerVM driver. This will ensure that if
a migration or resize is taking place on the same host, a temporary mac
address will be assigned to the original LPAR so there is no conflict on
the VIOS when a second LPAR is started with the same address.

Change-Id: I59db484defb789f3a7c0eddbd5ef9e92efc22419
(cherry picked from commit 2a43c4020927c936ed3b3f07416413f5171d62f8)
libvirt: Get driver type from base image type.

If we are using the raw backend (no cow), we should set the driver
type based on the type of the source image instead of always
using raw.

Calls to to_xml were moved after _create_image so that the image
type could be determined when creating the xml for libvirt.

Fixes bug 1163009

Change-Id: Ic8d5f0ab83d868a42f834d39c0afb64818d7e027
(cherry picked from commit 494a3cb5749d52aa90daeacd980362df5f971c0d)
Merge "Resolve conflicting mac address in resize" into stable/grizzly
Merge "libvirt: Get driver type from base image type." into stable/grizzly