tweak build_gems task
tweak build_gems task

rickypai/zookeeper,rickypai/zookeeper,songling88/zookeeper,songling88/zookeeper,songling88/zookeeper,rickypai/zookeeper,rickypai/zookeeper,songling88/zookeeper,zk-ruby/zookeeper,zk-ruby/zookeeper,zk-ruby/zookeeper