We use it as a json parser, for calc cell styles and tests. Making it
optional is just making the code more complex and introduces more
sources for errors.

Change-Id: I8769628a4ab9519cafc3d43db7c0007e0aa265dc
Reviewed-on: https://gerrit.libreoffice.org/31307Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>