check_once_cc_ccache_clear_kdc_time_offset
check_once_cc_ccache_clear_kdc_time_offset(ccache, cc_credentials_v5, ccNoError, "clearing an offset that was never set (v5)");
check_once_cc_ccache_clear_kdc_time_offset(ccache, cc_credentials_v5, ccNoError, "clearing v5");
cc_int32 check_once_cc_ccache_clear_kdc_time_offset(cc_ccache_t ccache, cc_int32 credentials_version, cc_int32 expected_err, const char *description);