After the gettext migration there is no point to have two
APIs for reading the same .mo file.

This patch is for sc/qa for easier review.

Change-Id: Ifd773700654565ad31424dfe854bee8486a2330b
Reviewed-on: https://gerrit.libreoffice.org/54095Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>