Missing firefox references in icecat-l10n

[Rubén Rodríguez]

There are some references to Firefox in the icecat-l10n deb tarball,
that are shown in the about window.

They can be set to empty strings with the script at the end of this:
http://bzr.trisquel.info/package-helpers/helpers/natty/make-icecat-l10n

The rest of the helper just puts the script in place and generates a
set of transitional packages providing firefox-locale-$LANG.