message: Add null check to start_login
diff: @@ -351,7 +351,9 @@ module.exports = React.createClass({
  this.notifyNewScreen('register');
  break;
  case 'start_login':
  - if (MatrixClientPeg.get().isGuest()) {
  + if (MatrixClientPeg.get() &&
  + MatrixClientPeg.get().isGuest()
  + ) {
  this.setState({
  guestCreds: MatrixClientPeg.getCredentials(),
  });
  