Updating redis.conf.jinja to redis v2.8.5

I tried to use the redis formula today, but was presented with the following error in /var/log/upstart/redis-server.log: 

```
*** FATAL CONFIG FILE ERROR ***
Reading the configuration file, at line 38
>>> 'vm-enabled no'
Bad directive or wrong number of arguments
```

The current stable version of redis is v2.8.5. According to the documentation it appears that redis v2.4 was the last version of redis to support virtual memory, and redis v.2.8.5 chokes on config options related to virtual memory.(http://redis.io/topics/virtual-memory)

I removed the configuration options related to vm and added the other options that existed in the v2.8.5 config that were not in redis.config.jinja.