When using roundup-admin to create a new tracker home
using an existing tracker home as a template (see bug
827497) I noticed that
roundup.install_util.copyDigestedFile() adds another
SHA hash even though a correct hash already exists.

It should either don't touch an existing hash, or only
touch it if the has isn't correct, because the file has
been altered.

templates/classic/html/style.css already contains two
hashes which becomes three during creating the tracker
home.
A few other files already contain a hash, too.
Attached is a patch to remove these existing hashes
which applies to maint-0-6 and HEAD.