to customize you must put a favicon file in your virtual file system.
i just had a look at your hfs and i don't think you did this.
if you instead want to really remove it you can
1. put a fake/empty favicon file, or
2. use an event script like this
[+request]
{.if|{.%url% = /favicon.ico.}|{:{.disconnection reason|no favicon please.}:}.}
untested!