zapit: add missing delete ait

Possible leak detected with LeakSanitizer


Origin commit data
------------------
Commit: be371fd8ca
Author: Thilo Graf <dbt@novatux.de>
Date: 2021-09-30 (Thu, 30 Sep 2021)

src/zapit/src/zapit.cpp

@@ -148,6 +148,9 @@ CZapit::CZapit()
 
 CZapit::~CZapit()
 {
+#if ENABLE_AIT
+	delete ait;
+#endif
 	Stop();
 }