IndexError in workers/sync.py

[berkerpeksag]

I got this when I ran gunicorn echo:app from the examples directory:

Traceback (most recent call last):
  File "/home/berker/projects/gunicorn/gunicorn/arbiter.py", line 574, in spawn_worker
    worker.init_process()
  File "/home/berker/projects/gunicorn/gunicorn/workers/base.py", line 140, in init_process
    self.run()
  File "/home/berker/projects/gunicorn/gunicorn/workers/sync.py", line 124, in run
    self.run_for_one(timeout)
  File "/home/berker/projects/gunicorn/gunicorn/workers/sync.py", line 59, in run_for_one
    listener = self.sockets[0]
IndexError: list index out of range

It works as expected if I revert 0be7996.