I had postponed that to post-freeze time since 95% of the work had to
be done server-side, and the required change to the Tails Git repo
is merely adjusting tbb-dist-url.txt.
Now that the infrastructure side is ready, we can use a permanent
location we control to fetch Tor Browser tarballs from at ISO
build time.
Assigned to anonym, who'll want to crash test the updated release doc
when importing Tor Browser 4.0.4 => candidate for 1.3.
