sudo not available after configuring ipmi serial over lan

[Eric Borisch]

What I find interesting is that with the 'wrong' setting, you can log still
in just fine, and run most commands, but 'sudo' alone fails as described
above. (I've had the same experience on Serial-over-IPMI, but 'su' worked
fine so I never dug into it.)

It's an easy fix, but I'm still (academically) interested in what it is
that sudo is doing that is unique.

 - Eric