Fix: flag metadata stream on quiescent control cmd

For the relayd, when doing a quiescent control command, we have to flag
the corresponding metadata stream or else it will simply stay alive
until a close stream and always returning that data is inflight at the
end data pending command.

Add a stream id to the relayd command so the relayd can identify which
stream to flag.

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