Add replacement for krb5_find_authdata()
    
    krb5_find_authdata() is only available in MIT Kerberos 1.10 or higher.
    To allow sssd to be compiled on platform with lower version of MIT
    Kerberos a replacement call is added. Please note that on those
    platform the replacement call will only return an error. If the
    krb5_find_authdata functionality is really needed on those platform it
    must be implemented by a different patch.