Allow using newer packages
    
    Cloud variant is now enabled as well. It will create repository from a
    special tag with some newer packages and run lorax on them. This install
    tree will then be used for building images. The repos still point the
    the original location outside of compose. The updates repo is used as
    well.
    
    For ostree installer, a runroot tag should be used that includes newer
    packages as needed. This tag is shared for both ostree installer and
    buildinstall. Using different tags would require a code change in Pungi.
    
    Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>