engine:Trusted Compute Pools - Open Attestation integration with oVirt engine

Detailed description: http://wiki.ovirt.org/Trusted_compute_pools

Add Audit log message when moving a VM between trusted and non-trusted clusters (or non-trusted to trusted).

Change-Id: I477f0c76a011473ed0802b8e4a23738e34e52e18
Signed-off-by: Gang Wei <gang.wei@intel.com>
Signed-off-by: Emily <lijuan.zhang@intel.com>