bug#6613: 23.2; bogus let bound var in gnus-delay.el

[Leo]

In the function `gnus-delay-article' in gnus-delay.el,

  (let ((group (format "nndraft:%s" gnus-delay-group)))
      (gnus-agent-queue-setup gnus-delay-group))

The let-bound var `group' is not used and in fact gnus-agent-queue-setup
takes care of formatting the group name already. So I think it should be
simplified to

  (gnus-agent-queue-setup gnus-delay-group)

Leo