docs: def up(queue, host=None):
      '''Up a queue, by removing a down file -- if a queue has no down file,
         this function is a no-op.'''
      down_path = fsq_path.down(queue, host=host)
      _queue_ok(os.path.dirname(down_path))
      try:
          os.unlink(down_path)
      except (OSError, IOError, ), e:
          if e.errno != errno.ENOENT:
              raise FSQConfigError(e.errno, wrap_io_os_err(e))