update to point to the new location of awkdiff since it's no longer
present in scottl's public_html...

The bad thing about svnweb is that it doesn't expand the FreeBSD
keyword unlike on checkout, so people using this d/l link won't have
it..


git-svn-id: svn+ssh://svn.freebsd.org/doc/head@45530 c2e8774f-c49f-e111-b436-862b2bbc8956