Fix: check lttng-modules ABI version for RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS support

Fix: check lttng-modules ABI version for RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS support

The RING_BUFFER_SNAPSHOT_SAMPLE_POSITIONS was introduced in
lttng-modules ABI version 2.3. When interacting with a kernel tracer
with ABI versions < 2.3, pass zero as monitor_timer_interval to disable
the monitoring.

Warn during sessiond startup and channel enabling if not supported.

Fixes #1101

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