Don't use SSLv23_server_method in an example

The function SSLv23_server_method() is an old name. New code should use
TLS_server_method() instead. Therefore don't use SSLv23_server_method() in
an example in the docs.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

doc/ssl/SSL_CTX_new.pod

@@ -73,7 +73,7 @@ those functions instead.
 The list of protocols available can later be limited using the
 SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1, SSL_OP_NO_TLSv1_1 and SSL_OP_NO_TLSv1_2
 options of the SSL_CTX_set_options() or SSL_set_options() functions.
-Using these options it is possible to choose e.g. SSLv23_server_method() and
+Using these options it is possible to choose e.g. TLS_server_method() and
 be able to negotiate with all possible clients, but to only allow newer
 protocols like TLSv1, TLSv1.1 or TLS v1.2.