現在已經支持直接自動連接到replica-set，並登錄primary
比如：
mongo --host rs1/vm1:27017,vm3:27017,vm4:27017 db_name然後會看到一堆信息
Thu Dec 12 16:44:48.227 successfully connected to seed vm1:27017 for replica set rs1 Thu Dec 12 16:44:48.228 changing hosts to { 0: "vm1:27017", 1: "vm4:27017", 2: "vm3:27017" } from rs1/ Thu Dec 12 16:44:48.228 trying to add new host vm1:27017 to replica set rs1 Thu Dec 12 16:44:48.229 successfully connected to new host vm1:27017 in replica set rs1 Thu Dec 12 16:44:48.229 trying to add new host vm3:27017 to replica set rs1 Thu Dec 12 16:44:48.232 successfully connected to new host vm3:27017 in replica set rs1 Thu Dec 12 16:44:48.232 trying to add new host vm4:27017 to replica set rs1 Thu Dec 12 16:44:48.234 successfully connected to new host vm4:27017 in replica set rs1 Thu Dec 12 16:44:48.240 Primary for replica set rs1 changed to vm1:27017 Thu Dec 12 16:44:48.247 replica set monitor for replica set rs1 started, address is rs1/vm1:27017,vm3:27017,vm4:27017 Thu Dec 12 16:44:48.247 [ReplicaSetMonitorWatcher] starting
