Fix: bad protocol flow between sessiond and consumerd

Also, the error handling was wrong for some error path.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: update lttng.1 man page

Fixes #571

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: don't stop a session that was not previously started

Fixes #567

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: clarify tracefile size/count in lttng.1 man

Fixes #572

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: destroy default created channel if add-context fails

Fixes #554

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: add debug statement in kernel flush metadata

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: bad type for the relayd id

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