[krbdev.mit.edu #5697] make ccache handle referrals better

[Sam Hartman via RT]

>>>>> "Jeffrey" == Jeffrey Altman via RT <rt-comment at krbdev.mit.edu> writes:

    Jeffrey> Tom Yu via RT wrote:
    >> Ouch.  It looks like t_cc fails because it attempts to use some
    >> human-readable strings instead of valid ASN.1 for the actual
    >> encoded "ticket" when storing a credential.

    Jeffrey> Note that kx509 stores X.509 certificates in the cache
    Jeffrey> using krb5_cc and there is at least one site that is
    Jeffrey> using the ccache to store SSH private keys.

It's not clear we support any of these use cases.