restore stats parameter for expire in Issue #1026.

1] Problem: to fix issue #1026, dictfind is changed to lookupKeyRead
 but, in lookupKeyRead, it changes server.stat_keyspace_misses and server.stat_keyspace_hits

2] Patch:
 so, this patch just decrease  server.stat_keyspace_misses and server.stat_keyspace_hits by 1, accoding to cases.