nginx: [alert] Unable to start the Phusion Passenger watchdog because its executable (/root/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/passenger-4.0.42/buildout/agents/PassengerWatchdog) does not exist. This probably means that your Phusion Passenger installation is broken or incomplete, or that your 'passenger_root' directive is set to the wrong value. Please reinstall Phusion Passenger or fix your 'passenger_root' directive, whichever is applicable. (-1: Unknown error)