Fix: chunk state is not set when relayd does not support trace chunks

Being explicit here enforces that for a lttng-relayd that does not
support chunks, the queried chunk will never exist.

This caused a lttng destroy command to hang during backward
compatibility testing with older lttng-relayd.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>