Description of problem:

Installed Fedora 17 Beta and chose customized install with eclipse added in.
After first boot, the user jetty shows up as a possible login instead of being invisible like other system accounts.
Reinstalled and confirmed account shows up.

I believe the issue is due to 

jetty:x:995:992::/usr/share/jetty:/bin/sh

and jetty having a bourne shell. I expect it needs to have a nologin script especially for security reasons in various audits.