Ensure deploy directory exists

deploy directory must be exist before running dotenv recipe.
For rails app layer, `unicorn::rails` recipe does this. see https://github.com/aws/opsworks-cookbooks/blob/release-chef-11.10/unicorn/recipes/rails.rb#L19

But for delayed_job, there're no existing recipe that creates deploy directory in setup recipes. So we can't use dotenv recipe in setup phase without this pull request.

Actually I haven't test that this change works correctly...