The repository used by the texlive installer defaults to a redirector
that sends one off to various URLs depending on <fill in the blank>.
This is problematic because all of the mirrors do not update in
synchrony and bad tarballs often hang around for a while.
This leads to problems that are particularly hard to diagnose because
you're likely to end up using a different repo the next time around.
This commit constraints the package to a particular, mainstream,
repository. It's not fast, but it's consistent and usually correct.
It also updates the installer digest, because no day is complete
without updating it at least (sigh) once.
b28d8345ec