InvalidCPUInfo exception added to except block

When a live migration between two nodes with different
CPU info features is launched, an InvalidCPUInfo exception
is raised and not captured. That lets the vm in an
unusable state because the task_state rollback is not
executed.

Change-Id: Ib418fa324964cabd5f342d1b764f9ac7608b7ade
Closes-Bug: #1294210
Merge "InvalidCPUInfo exception added to except block"