fix acl issue

[jammyWolf]

First of all, I think your zookeeper_dashboard is very friendly and useful. But a project i encountered needs to support a list of clusters rather than one. So, i forked your code, then refactored it (https://github.com/jammyWolf/zookeeper_dashboard.git). I changed the logic of your code but remains the web design part. My version supports multiple clusters and acl_control (thanks to kazoo's auth_data params). Finally, I‘m a beginner in zookeeper, could you help me in reviewing the code and give me some advises. Thanks!