Remove untranslated PO files

The proposal bot only imports file that are at least 75 % translated.
Remove any PO file that is untranslated or has less than 75 % of
translations.
This actually removed *all* files.

Checked number of translated entries with:
cd ironic/locale
for i in `find . -name *.po `; do echo $i;msgfmt --statistics $i; done

See also https://www.transifex.com/projects/p/ironic/ for current
translation state.

Whenever a file is again translated sufficiently, the proposal bot will
propose a new patch - thus we do not lose any translations.

Change-Id: I9319c37d8af11a2163528c60e3a2bb0a84db4f21
Merge "Remove untranslated PO files"