Redirect alpha and hardened channels to dist.tpo rather than aus1.tpo
A few months ago we added the following redirects:
1. https://www.torproject.org/dist/torbrowser/update_2/alpha/ --> https://aus1.torproject.org/torbrowser/update_2/alpha/
2. https://www.torproject.org/dist/torbrowser/update_2/hardened/ --> https://aus1.torproject.org/torbrowser/update_2/hardened/
3. https://dist.torproject.org/torbrowser/update_2/alpha/ ---> https://aus1.torproject.org/torbrowser/update_2/alpha/
4. https://dist.torproject.org/torbrowser/update_2/hardened/ ---> https://aus1.torproject.org/torbrowser/update_2/hardened/
Because there is no pinning on aus1.tpo yet, we want to move the `alpha` and `hardened` channels URLs back to dist.tpo (like the `release` channel). The redirects 1. and 2. should be modified to point to https://dist.torproject.org/torbrowser/update_2/alpha/ and https://dist.torproject.org/torbrowser/update_2/hardened/. The redirects 3. and 4. should be removed.
Currently the xml files are deployed in both locations, so that it continues to work after the redirects are updated:
- /srv/dist-master.torproject.org/htdocs/torbrowser/update_2/alpha
- /srv/aus1-master.torproject.org/htdocs/torbrowser/update_2/alpha
issue