message: EventIndex: Remove a checkpoint if the HTTP request returns a 403.
  This fixes
diff: @@ -373,6 +373,21 @@ export default class EventIndex extends EventEmitter {
  checkpoint.roomId, checkpoint.token, this._eventsPerCrawl,
  checkpoint.direction);
  } catch (e) {
  + if (e.httpStatus === 403) {
  + console.log("EventIndex: Removing checkpoint as we don't have ",
  + "permissions to fetch messages from this room.", checkpoint);
  + try {
  + await indexManager.removeCrawlerCheckpoint(checkpoint);
  + } catch (e) {
  + console.log("EventIndex: Error removing checkpoint", checkpoint, e);
  + // We don't push the checkpoint here back, it will
  + // hopefully be removed after a restart. But let us
  + // ignore it for now as we don't want to hammer the
  + // endpoint.
  + }
  + continue;
  + }
  +
  console.log("EventIndex: Error crawling events:", e);
  this.crawlerCheckpoints.push(checkpoint);
  continue;
  