Add trace events to dump the key content.
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>
Message-Id: <20190422195020.1494-2-philmd@redhat.com>
Signed-off-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>