pass failure across in T.38 passthru mode

src/mod/endpoints/mod_sofia/sofia.c

@@ -4414,7 +4414,7 @@ static void sofia_handle_sip_r_invite(switch_core_session_t *session, int status
 		
 		if (switch_channel_test_flag(channel, CF_PROXY_MODE) || 
 			switch_channel_test_flag(channel, CF_PROXY_MEDIA) || 
-			(sofia_test_flag(tech_pvt, TFLAG_T38_PASSTHRU) && has_t38)) {
+			(sofia_test_flag(tech_pvt, TFLAG_T38_PASSTHRU) && (has_t38 || status > 299))) {
 
 			if (sofia_test_flag(tech_pvt, TFLAG_SENT_UPDATE)) {
 				sofia_clear_flag_locked(tech_pvt, TFLAG_SENT_UPDATE);