Bash test fix for su nobody

[Bruce Dubbs]

Dan Nicholson wrote:

> One remaining question is, which device to attach to? I noticed that
> perl redirects /dev/tty to stdin during its tests, and Bryan says this
> should always be readable to all users. I'm clueless on terminal
> devices, so if anyone wants to make suggestions, pipe up.

/dev/tty seems to always have 666 permissions on several systems I
checked.  That seems to make the most sense.  /dev/null may work, but I
think most users will have less questions about tty.

  -- Bruce