Change modern distro versions for PPC

This patch changes the version of modern distro for PPC to RHEL >= 6.5
and SLES >= 11 SP3. Modern distro in PPC can use virtio.

Signed-off-by: Rodrigo Trujillo <rodrigo.trujillo@linux.vnet.ibm.com>
Disable vhost feature in Ubuntu and SLES (PPC64 LE)

There are know issues related to vhost feature and Little Endian
distros. This patch sets driver name='qemu', disabling the vhost
feature when libvirt starts a virtual machine.
LE Distros: Ubuntu >= 14.04 and SLES >= 12.

Signed-off-by: Rodrigo Trujillo <rodrigo.trujillo@linux.vnet.ibm.com>