I have here a site that uses the po plugin, and recently had this change
committed to its setup:

<pre>
 po_slave_languages:
 - de|Deutsch
 - fr|Français
-- ja|日本語
-- tr|Türkçe
</pre>

The change was made by the web UI, so it must have involved a site rebuild
at the time, as that configuration item has `rebuild => 1`.

Some days after that config change, a push caused ikiwiki refresh to fail:

    remote: /home/b-udm/public_html/Discussion/index.ja.html independently created, not overwriting with version from Discussion.ja

Rebuilding the wiki cleared that up, but it seems that po plugin config
changes can lead to follow-on problems of this sort.

The site still has a `source/index.ja.po`. And it has
`public_html/index.ja.html`, as well as `public_html/index.ja/index.html`.

--[[Joey]]
