Explain the effect of OPT_X_TLS_PROTOCOL_MIN
    
    OpenLDAP 2.4 sets minimum version with SSL_CTX_set_options(). The
    system-wide crypto-policies for TLS minimum version are applied
    with SSL_CTX_set_min_proto_version(). The set_option() call cannot
    not enable lower versions than allowed by crypto-policy, e.g.
    openssl.cnf MinProtocol=TLS1.2 + OPT_X_TLS_PROTOCOL_MIN=TLS1.0
    result in TLS 1.2 as minimum protocol version.
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>