The core state machine was broken - it didn't free resources
in START -> DOWN transition and might freed resources after
UP -> STOP transition before protocol turned down. It leads
to deadlock on olock acquisition when lock was not freed
during previous stop.
The current behavior is that resources, allocated during
DOWN -> * transition, are freed in * -> DOWN transition,
and flushing (scheduled in UP -> *) just counteract
feeding (scheduled in * -> UP). Protocol fell down
when both flushing is done (if needed) and protocol
reports DOWN.
BTW, is thera a reason why neighbour cache item acquired
by protocol is not tracked by resource mechanism?
neighbor->scope now contains proper address scope which is zero (SCOPE_HOST)
for local addresses, higher (SCOPE_LINK, ..., SCOPE_UNIVERSE) for remote ones.
