streams_sent

almost working, kernel seems good, for ust : the metadata stream is sent
after the stream_sent, so wrong place.
also the ust snapshot test seems to fail.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
tmp commit

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>