Fix again the download pointer in the release branch.

The pointer was only corrected in the master branch. Also the tag should be set to be pointing to the
release branch. In order to fix this you should do after you've merged this pull request:

    git checkout release
    git pull origin/release
    git tag -d v1.2.0  # removes the old tag
    git tag v1.2.0 # resets the tag at the current position, i.e., tip of release branch
    git push --force --tags # force upgrade is needed because the existing tag needs to be rewritten