增加flume-log-sdk的高可用，使用zookeeper保证flume-agent挂掉后能够自动通知到
flume-log-sdk中，并且对flume的代码加入了对zookeeper的使用，注册对应的mappingchannel的agent节点
	modified:   config/zk_manager.go
	modified:   config/zk_manager_test.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
	modified:   main/bootstrap.go
	modified:   main/start.sh