Fix data pending for inflight streaming

The consumer_data_pending() function call had a bad label naming. The
goto label data_not_pending was actually going to the return value of
pending data (1). So, this patch fixes that by renaming the label to the
right meaning.

Add a missing destroy of the relayd session id mapping hash table.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>