COOK-1374 sv-unicorn-run.erb should use runit attributes

templates/default/sv-unicorn-run.erb

@@ -3,5 +3,5 @@
 cd <%= @options[:app]['deploy_to'] %>/current
 
 exec 2>&1
-exec chpst -u <%= @options[:app]["owner"] %>:<%= @options[:app]["group"] %> <%= @options[:smells_like_rack] ? 'unicorn' : 'unicorn_rails' %> -E <%= @options[:rails_env] %> -c /etc/unicorn/<%= @options[:app]['id'] %>.rb
+exec <%= node[:runit][:chpst_bin] %> -u <%= @options[:app]["owner"] %>:<%= @options[:app]["group"] %> <%= @options[:smells_like_rack] ? 'unicorn' : 'unicorn_rails' %> -E <%= @options[:rails_env] %> -c /etc/unicorn/<%= @options[:app]['id'] %>.rb