Set the log path, config path, data path to the default 10 gen repo 

When we chef solo this cookbook, we will get duplicated mongo log, config file, and data dir and it's quite frustrating.
I am not sure why you will use different paths for these.
So I changed: 

Config
/etc/mongodb.conf -> /etc/mongod.conf
Log
/var/log/mongodb/mongodb.log -> /var/log/mongo/mongod.log
Data
/var/lib/mongodb -> /var/lib/mongo

Also, with latest mongo (2.9.x), we will see warnings when we start the mongo:
```
Starting mongod: 
warning: remove or comment out this line by starting it with '#', skipping now : nojournal = false
warning: remove or comment out this line by starting it with '#', skipping now : rest = false
warning: remove or comment out this line by starting it with '#', skipping now : smallfiles = false
warning: bind_ip of 0.0.0.0 is unnecessary; listens on all ips by default
```
So I set the default value of `nojournal`, `rest`, `smallfiles`, and `bind_ip` to `nil`.