master won't build without V2_HANDSHAKE_SERVER

master won't build without V2_HANDSHAKE_SERVER:

tortls.c:1525:40: error: ‘tor_tls_debug_state_callback’ undeclared (first use in this function)
tortls.c:1525:40: note: each undeclared identifier is reported only once for each function it appears in

This happens because without V2_HANDSHAKE_SERVER, tor_tls_debug_state_callback is not defined and it's not visible when tor_tls_new() tries to do:

 SSL_set_info_callback(result->ssl, tor_tls_debug_state_callback);

This bug was introduced in 410e440a8d40e556cc445a1ecc6a8ed4109434b6, and simply always defining tor_tls_debug_state_callback (and not only when V2_HANDSHAKE_SERVER`) should fix it.