Uses the HTTPS url for cases where the existing URL has a permanent
redirect. For each domain, at least one fixed derivation URL was
downloaded to test the domain is properly serving downloads.
Also fixes jbake source URL, which was broken.
Fixes this:
$ nix-env -f . -qa \* --meta --xml --drv-path --show-trace >/dev/null
...
error: while querying the derivation named ‘pypy2.5-graph-tool-2.2.36’:
while evaluating the attribute ‘preConfigure’ of the derivation ‘pypy2.5-graph-tool-2.2.36’ at "/home/bfo/nixpkgs/pkgs/development/python-modules/graph-tool/2.x.x.nix":5:3:
attribute ‘sitePackages’ missing, at "/home/bfo/nixpkgs/pkgs/development/python-modules/graph-tool/2.x.x.nix":22:54