I'm not sure how this patch fixes a bug where ticket renewal times are 24 hours.  KIM (and KLL, 
which this code was copied from) is hardcoding a default of 7 days.  So while this patch does 
get rid of a duplicate default value, I am concerned that it is not actually fixing the bug 
described in the subject line.

Also as far as code readability goes, I'd like to see the kim_default_renewal_lifetime macro 
remain in the code and be set to 0 with a comment explaining that the krb5 libraries treat a 
renewable lifetime of 0 as "use the default renewal lifetime" when KDC_OPT_RENEWABLE is set.  
The patch just sets a 0 in the initializer structure with no explanation as to what it means.  This 
increases the likelihood that future programmers will break the code while trying to modify its 
behavior.