ISPN-2420 Increment the topology id when a node leaves the cache

Needed for the ISPN-2632 fix with replicated caches - since they don't
rebalance after a leave, they will never send a topology update to their
clients.
ISPN-2632 Uneven request balancing after node crash

Send the cache topology id to the client instead of the JGroups view id.
There's a problem with replicated caches for now, because they don't
increment their topology id after a leave.