Redirect non-ssl apt requests to non-ssl bucket.

Redirects from non-ssl to ssl won't be followed by apt-get, so we
should allow bare http requests to remain that way. All our packages
are signed, so there shouldn't be any danger in bare-http package
downloads; any attempts by an attacker to modify the packages would be
detected at install time.

We have users out there who are using the https URLs, so we don't want
to break those by forcing non-ssl; we should simply propagate the
sslness of the given request.