[krbdev.mit.edu #6343] klist should mark expired tickets

[Russ Allbery <rra@stanford.edu> via RT]

This is Debian bug http://bugs.debian.org/482522

Heimdal klist shows expired tickets by replacing the ticket expiration
time with a string indicating the ticket is expired.  With MIT klist,
you have to read the expiration time and notice that it was in the past.
 It would be nice to show something similar.

One option would be to show >>EXPIRED<< by default and provide a switch
to show the actual expiration time.  Another would be to follow the
formatting of renewable tickets and do something like:

Valid starting     Expires            Service principal
01/23/09 16:14:04  >>EXPIRED<<        krbtgt/stanford.edu at stanford.edu
        expired at 01/23/09 16:20:04