Remove consumer poll timeout in data thread

This was originally used to stop any poll() after a grace period when a
session daemon dies in case of weird stuck fd(s).

However, things have changed a bit especially on the UST tracer side
where all stream handles are now cleaned up if the session daemon socket
hang up which than release every stream on the consumer and finally
quits gracefully.

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