Bump nginx recipe to 2.7.4 to avoid dependency lookup failure.

The dependencies of 2.2.0 were in conflict with other dependencies, so librarian-chef would end up in an endless loop of trying to solve an unsolvable dependency resolution.
Create config dirs inside "#{app.shared_path}/config".

Originally set to "#{app.current_path}/config", which doesn't yet exist until after a successful Capistrano deploy, so Chef would fail due to the non-existence of "#{app.current_path}"