Backwards interop for older iprop peers

Don't abort() when seeing as-yet-unimplemented things we know about.

Patch from Harald Barth <haba@kth.se>.
Use KRB5_TC_MATCH_TIMES when looking for creds
Set cc config creds endtime to MAX
Do use KRB5_TC_MATCH_TIMES in krb5_cc_get_config()
Make fcc_remove_cred() better

Don't use a memory ccache go between, just copy all but the matching
credential(s).
Use krb5_timeofday() in kuser/copy_cred_cache.c
Add options to kcpytkt and kdeltkt for exp tix
Make kinit cmd not exit on transient errors
Allow batch mode in kinit with password file
kinit should save cc configs if it krb5_cc_move()s

Also, renew_validate() should krb5_cc_new_unique() and krb5_cc_move() it
into place.
kinit cmd: back-off more slowly and warn

Also refactor AFS klog code so we do it only once on renew.