gnome-taquin: Build Failure

[Jiro Matsuzawa <jmatsuzawa gnome org>]

Hi Piotr Drąg and French translators
(CC'd Arnaud Bonatti)

gnome-taquin fails to build the help because of invalid HELP_LINGUAS.
The following is the error message:
```
make[1]: Entering directory '/opt/gnome/checkout/gnome-taquin/help'
  GEN      fr/fr.po
Error: cannot open XML file C/15-Puzzle.page
Makefile:485: recipe for target 'fr/fr.po' failed
make[1]: *** [fr/fr.po] Error 1
```

The help pages are translated into French and HELP_LINGUAS has fr.
However, gnome-taquin does not have help/fr/fr.po but static
help/fr/*.page.

I think we should revert c3e5007 [1] to remove fr from HELP_LINGUAS.
If fr.po can be provided before the tarball due, that would be better.

[1]: https://git.gnome.org/browse/gnome-taquin/commit/?id=c3e5007da2b696e9b26679c6ecf1dd7e40796765

-- 
Jiro Matsuzawa
Email: jmatsuzawa at gnome.org
GPG Key ID: 0xECC442E9