Move session ticket keys to conf

This is temporary, they will soon be replaced by callbacks.
!!! In this intermediate step security is removed !!!
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 5f5033a..e5fcfdf 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -1590,7 +1590,7 @@
 #endif
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    if( ( ret = mbedtls_ssl_set_session_tickets( &ssl, opt.tickets ) ) != 0 )
+    if( ( ret = mbedtls_ssl_set_session_tickets( &conf, opt.tickets ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_ssl_set_session_tickets returned %d\n\n", ret );
         goto exit;