for READ_AHEAD_GAP, and calling storeCheckSwapout() in
storeBufferFlush(). Otherwise, the read-past pages would
never be freed.
+ - Fixed DNSSERVER shutdown bugs. The re-opened dnsserver processes
+ were being closed by the dnsServerShutdown event.
- Modified storeHashInsert() to insert PRIVATE objects at
the tail of the LRU list, and PUBLIC objects at the head.
Thus, PRIVATE objects get kicked out quicker.