Regression from commit d5c934d1
(n#792778 DOCX import: parse group shapes in oox only, 2012-12-14),
where where manual wordprocessingML -> drawingML translation did not
handle this character property.

Change-Id: I87481bc9c26651fd15dd39a58a92f467e8311256
Reviewed-on: https://gerrit.libreoffice.org/65289
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>