Fix: relayd refcount updates for stream

Increment refcount only when the stream was successfully sent to the
relayd and set the new stream's flag "sent_to_relayd" which is used
before the refcount update when closing the relayd. A stream that was
unable to be sent, the close relayd code path does not decrement the
refcount anymore.

Signed-off-by: David Goulet <dgoulet@efficios.com>