gschema: Fix inclusion of translation comment in .pot file
requested to merge Vanadiae/epiphany:fix-gschema-search-engines-translator-comment-inclusion into master
Fixes #1676 (closed)
It was probably more because of the CDATA part that confused xgettext, more than just adding text to existing comment (so it would be more fbde9b18 that broke it than a25f4f68).