- switch to the version of persistent-keyring that was just merged to
master (RT#7711), along with related changes to kinit (RT#7689)
- go back to setting default_ccache_name to a KEYRING type
- pull in upstream fix to start treating a KRB5CCNAME value that begins
with DIR:: the same as it would a DIR: value with just one ccache file
in it (RT#7172, #965574)