fix a couple of more memory leaks that valgrind found

libtransmission/tracker.c

@@ -924,6 +924,9 @@ onTrackerResponse( struct evhttp_request * req, void * vtor )
         reannounceInterval = isStopped
             ? -1
             : tor->tracker->announceIntervalMsec;
+
+        if( bencLoaded )
+            tr_bencFree( &benc );
     }
     else
     {

libtransmission/trevent.c

@@ -90,6 +90,7 @@ readFromPipe( int fd, short eventType UNUSED, void * unused UNUSED )
             read( fd, &event, sizeof(struct event*) );
             tr_dbg( "read del event from pipe: event is %p", event );
             event_del( event );
+            tr_free( event );
             break;
 
         case 'e': /* event_add */