Doesn't need sudo here. Use su (useful for rbenv). Don't hide errors

Switch from 'sudo' to 'su -'
It loads environment and if there's rbenv installed for app user it'll pick it up.
Also stop hiding errors. It's impossible to debug if start script sends all the output to `/dev/null`
How about we we redirect the stdout/stderr to something like '<%= "#{node["lita"]["log_dir"]}/console.log" %>' (or daemon.log or whatever) instead of just letting it hit the console?