Fix: remove nonblock flag of sessiond socket in consumer

There is no need for non blocking socket. Furthermore, we have observed
unstable behaviors with a non blocking side (consumer) and a blocking
side (sessiond).

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: poll compat layer reallocation new size

The size was doubled but in fact it should have been checked for the
maximum between the number of fd doubled and the alloc size doubled
(divised by two when shrinking the buffer).

Same goes for the shrink process. For that, get_count_order_u32() is
added to utils.c/.h.

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