disable SSL via named pipes in the internal client

because it doesn't work. CONC-635.

extra/mariabackup/backup_mysql.cc

@@ -132,7 +132,7 @@ xb_mysql_connect()
 	       opt_socket ? opt_socket : "not set");
 
 #ifdef HAVE_OPENSSL
-	if (opt_use_ssl && opt_protocol <= MYSQL_PROTOCOL_SOCKET)
+	if (opt_use_ssl)
 	{
 		mysql_ssl_set(connection, opt_ssl_key, opt_ssl_cert,
 			      opt_ssl_ca, opt_ssl_capath,

sql-common/client.c

@@ -2052,6 +2052,12 @@ static int send_client_reply_packet(MCPVIO_EXT *mpvio,
   if (mpvio->db)
     mysql->client_flag|= CLIENT_CONNECT_WITH_DB;
 
+  if (mysql->net.vio->type == VIO_TYPE_NAMEDPIPE)
+  {
+    mysql->server_capabilities&= ~CLIENT_SSL;
+    mysql->options.use_ssl= 0;
+  }
+
   /* Remove options that server doesn't support */
   mysql->client_flag= mysql->client_flag &
                        (~(CLIENT_COMPRESS | CLIENT_SSL | CLIENT_PROTOCOL_41)