修复了flume节点连接不上导致程序退出
	modified:   ../config/zk_manager.go
	modified:   ../config/zk_manager_test.go
	modified:   ../consumer/client/flume_client.go
	modified:   ../consumer/flume_node_watcher.go
	modified:   ../consumer/log_sink.go
	modified:   ../consumer/log_sink_manager.go
	modified:   ../consumer/log_sink_test.go
	modified:   ../consumer/pool.go
	modified:   ../consumer/pool_test.go