增加了zk读取flume agent的配置，并做了选取Master的flume agent保证高可用
代码写完编译成功，明天补齐test
	modified:   config/option.go
	modified:   config/zk_manager.go
	new file:   config/zk_manager_test.go
	modified:   consumer/log_sink.go
	new file:   consumer/log_sink_manager.go
	modified:   main/bootstrap.go
	modified:   main/start.sh