Let the yumconf.persistdir be as the default
    
    This path gets appended to the installroot every time,
    even if it's an absolute path, so it ends up being inside
    the installroot everytime. We don't want it to be in some
    path depending on a temporary workdir. This will put all
    the yum files in a standard /var/lib/yum directory inside
    the installroot.