sanitize viewdata col/row values

Change-Id: Iec51b032c96189b20cd43934c477b587da3011a7
(cherry picked from commit d042bef351af4649e656bfb8c60273149e5daeb5)
Reviewed-on: https://gerrit.libreoffice.org/13179
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>