It's emitted when the Virtual Machine resumes execution.

We currently have the STOP event but don't have the matching
RESUME one, this means that clients are notified when the VM
is stopped but don't get anything when it resumes.

Let's fix that as it's already causing some trouble to libvirt.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>