Another request from OZ to remove unicorn since its not used.

I am pretty sure that live community does not use the intuit/cookbooks/unicorn recipe... so I have opened this pull request.

BUT I AM NOT SURE so I included this info here:

This is what I found:
1) APP role requires "deploy_web_app"
2) deploy_web_app recipe has unicorn in it.

APP ROLE code:
https://github.com/live-community/live_community_chef_repo/blob/master/roles/app.rb#L9

deploy_web_app recipe:
https://github.com/live-community/live_community_chef_repo/blob/master/cookbooks/intu_lc/recipes/deploy_web_app.rb#L42