默认创建以$brokerName为名字的topic
fix memory leak #365
修改版本 3.0.9-DUMMY-SNAPSHOT 测试期间专用版本。
Merge remote-tracking branch 'origin/develop' into develop
修复isBlank工具类bug
fixed #378 Name Server地址设置错误情况下，拒绝启动broker。
Merge branch 'develop' of http://gitlab.alibaba-inc.com/middleware/rocketmq into develop