Never ship plugin.json.
    
    Keep the plugin.json always as ghost and create the
    %{_sharedstatedir}/vagrant/plugins.json file and
    %{_datadir}/vagrant/plugins.json symlink in %post. Also, let the
    scriplets always work with the symlink to the real file. This should
    provide better compatibility with rpm-ostree.
    
    The link could be dropped in F28-F29 timeframew:
    
    https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/SKJVY6KZYP24B4KOXLX3BBI5DWSJUEK5/