Commit dcb853ac32779b173f39e19c0f24b0087de85771 removed some replay
cache functions that haven't been considered part of the libkrb5 API.
Some of these functions were used in OpenSSL (despite the lack of
prototypes) prior to the OpenSSL 1.1 release. Run-time linker errors
can occur if an OpenSSL 1.0.x (or earlier) libssl is used with a 1.18
libkrb5, even though the Kerberos code would likely never be used.
Add stubs for the four functions historically used in OpenSSL.