message: Ensure http server thread is only stopped if it was started.
  Thread startup (StartHTTPServer) is separate  from
  initalization (InitHTTPServer), so we need to check whether the thread
  was started before stopping it.
  Fixes
diff: @@ -516,8 +516,11 @@ void StopHTTPServer()
  LOGA("HTTP event loop did not exit within allotted time, sending loopbreak\n");
  event_base_loopbreak(eventBase);
  }
  + if (threadHTTP.joinable())
  + {
  threadHTTP.join();
  }
  + }
  if (eventHTTP)
  {
  evhttp_free(eventHTTP);
  