message: Retrieve client configuration to check for a configured nick
diff: @@ -840,8 +840,11 @@ MatrixHandler.prototype._onJoin = Promise.coroutine(function*(req, event, user)
  // Changing the nick requires that:
  // - the server allows nick changes
  // - the nick is not custom
  + let config = yield self.ircBridge.getStore().getIrcClientConfig(
  + bridgedClient.userId, room.server.domain
  + );
  if (room.server.allowsNickChanges() &&
  - bridgedClient.getClientConfig().getDesiredNick() === null
  + config.getDesiredNick() === null
  ) {
  bridgedClient.changeNick(
  room.server.getNick(bridgedClient.userId, event.content.displayname),
  