message: remove `var` from _onEvent
diff: @@ -607,14 +607,14 @@ IrcBridge.prototype.onEvent = function(request, context) {
  };
  IrcBridge.prototype._onEvent = Promise.coroutine(function*(baseRequest, context) {
  - var event = baseRequest.getData();
  + const event = baseRequest.getData();
  if (event.sender && this.activityTracker) {
  this.activityTracker.bumpLastActiveTime(event.sender);
  }
  - var request = new BridgeRequest(baseRequest, false);
  + const request = new BridgeRequest(baseRequest, false);
  if (event.type === "m.room.message") {
  if (event.origin_server_ts && this.config.homeserver.dropMatrixMessagesAfterSecs) {
  - let now = Date.now();
  + const now = Date.now();
  if ((now - event.origin_server_ts) >
  (1000 * this.config.homeserver.dropMatrixMessagesAfterSecs)) {
  log.info(
  @@ -634,8 +634,8 @@ IrcBridge.prototype._onEvent = Promise.coroutine(function*(baseRequest, context)
  return BridgeRequest.ERR_NOT_MAPPED;
  }
  this.ircHandler.onMatrixMemberEvent(event);
  - var target = new MatrixUser(event.state_key);
  - var sender = new MatrixUser(event.user_id);
  + const target = new MatrixUser(event.state_key);
  + const sender = new MatrixUser(event.user_id);
  if (event.content.membership === "invite") {
  yield this.matrixHandler.onInvite(request, event, sender, target);
  }
  @@ -655,7 +655,7 @@ IrcBridge.prototype._onEvent = Promise.coroutine(function*(baseRequest, context)
  }
  }
  }
  - else if (event.type === "m.room.power_levels") {
  + else if (event.type === "m.room.power_levels" && event.state_key === "") {
  this.ircHandler.powerlevelSyncer.onMatrixPowerlevelEvent(event);
  }
  return undefined;
  