fix undefined method `num_waiting'  exception when resultqueue=[]

I try to deploy cloud foundry on my local computer by manual, first deploy gnastd, then gorouter, when I try deploy cloud controller, it throw a exception.
underline is  msg:
 /home/hushan/work/cf-release/src/cloud_controller_ng/lib/cloud_controller/varz.rb:60:in `get_thread_info': undefined method `num_waiting' for []:Array (NoMethodError)
	from /home/hushan/work/cf-release/src/cloud_controller_ng/lib/cloud_controller/varz.rb:25:in `update_thread_info'
	from /home/hushan/work/cf-release/src/cloud_controller_ng/lib/cloud_controller/varz.rb:9:in `block in setup_updates'
	from /var/lib/gems/1.9.1/gems/eventmachine-1.0.3/lib/em/timers.rb:56:in `call'
	from /var/lib/gems/1.9.1/gems/eventmachine-1.0.3/lib/em/timers.rb:56:in `fire'
	from /var/lib/gems/1.9.1/gems/eventmachine-1.0.3/lib/eventmachine.rb:187:in `call'
	from /var/lib/gems/1.9.1/gems/eventmachine-1.0.3/lib/eventmachine.rb:187:in `run_machine'
	from /var/lib/gems/1.9.1/gems/eventmachine-1.0.3/lib/eventmachine.rb:187:in `run'
	from /home/hushan/work/cf-release/src/cloud_controller_ng/lib/cloud_controller/runner.rb:84:in `run!'