Fix: destroy command: put consumer output after destroy notifier

The destroy notifier needs to access the consumer output to format
the absolute path to the last chunk.

The observed problematic behavior can be observed by doing a
rotate and a destroy command in quick succession. Sometimes,
the resulting path printed by the destroy command is incomplete:

e.g. /archives/20190920T163616-0400-20190920T163618-0400-1

when we would expect:

/home/efficios/lttng-traces/auto-20190920-164425/archives/20190920T164437-0400-20190920T164439-0400-1

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