Specify connect-redis version.

Viimane connect-redis ei toimi enam Express 3.x-ga.
https://github.com/visionmedia/connect-redis/issues/104

Hetkel käivitades viskab:
```
/opt/pangalink.net/node_modules/connect-redis/lib/connect-redis.js:96
  RedisStore.prototype.__proto__ = Store.prototype;
                                        ^
TypeError: Cannot read property 'prototype' of undefined
    at module.exports (/opt/pangalink.net/node_modules/connect-redis/lib/connect-redis.js:96:41)
    at Object.<anonymous> (/opt/pangalink.net/server.js:6:42)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (/opt/pangalink.net/index.js:35:5)
    at Module._compile (module.js:456:26)
```

Docker indexis olev image on ka 1.5.0-ga.