Use ulimit for all flavors

- clean old limits
- use ulimit for all flavors
Add `fi` that was mistakenly dropped during edit
Make modification to the `/etc/security/limits.conf` file opt-in
Scrub the `limits.conf` file by default and allow for opt-out
Update code block formatting from merge
Merge branch 'feature/source-defaults' of github.com:ninefold/chef-elasticsearch into feature/source-defaults