about/team.html: Fix id ('guy.t' -> 'gustavsen.j') for Julia Gustavsen

The previous id was probably a copy-paste error during:

  commit 9093f0ed0e87f7065ee7f1e38098858a587c0a13
  Author: Greg Wilson <gvwilson@third-bit.com>
  Date:   Tue Feb 5 22:55:54 2013 -0500

    Adding Julia Gustavsen