add lsb tags requested on debian (http://wiki.debian.org/LSBInitScripts)

Hi,

The LSB tags are missing on redis init script. It's usefull to build daemons that need redis to be started before.

Output on debian :

```
  $ sudo update-rc.d redis defaults
  insserv: warning: script 'redis' missing LSB tags and overrides
```

You can find more infos here :
http://wiki.debian.org/LSBInitScripts