Fix: consumer: put each chunk on teardown

Trace chunks in the registry may still exist because those are top-level
entities for which we may have received a "create" command from session
daemon without pairing "destroy". Iterate on the entire chunk registry
and put the sessiond reference for each chunk on consumerd teardown

Fixes the following assert on teardown caused by non-empty registry on
SIGINT:

lttng-consumerd: trace-chunk.c:1109: lttng_trace_chunk_registry_destroy: Assertion `!ret' failed.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>