Now we're not using the 'last' field in the timer, remove it from
replay.

Bump the version number of the replay structure since we've
removed the field.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190724115823.4199-4-dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>