message: Reset 'first sync' flag / promise on log in
  Otherwise on any logins after the first,we always think the first
  sync has completed.
diff: @@ -927,6 +927,8 @@ module.exports = React.createClass({
  dis.dispatch({action: 'view_home_page'});
  } else if (this._is_registered) {
  this._is_registered = false;
  + this.firstSyncComplete = false;
  + this.firstSyncPromise = q.defer();
  // Set the display name = user ID localpart
  MatrixClientPeg.get().setDisplayName(
  