[krbdev.mit.edu #7458] add more strftime format strings for klist

[Tom Yu via RT]

It's also worth noting that there's an fallback to use sprintf to format using the equivalent of 
"%d/%m/%Y %H:%M" if none of the strftime formats works.  We should probably remove this 
fallback sprintf format because it is ambiguous (European vs US date order).  Can we also 
assume a working strftime as well, considering that we appear to attempt to build a replacement 
if it's not found?