Do not null packet->out_frame, it might be in use. The packet manages…

… the frame

src/zm_monitor.cpp

@@ -2569,7 +2569,7 @@ bool Monitor::Analyse() {
  }
  }
  // Free up the decoded frame as well, we won't be using it for anything at this time.
- snap->out_frame = nullptr;
+ //snap->out_frame = nullptr;
  }
  } // end scope for event_lock
  delete packet_lock;