Gets rid of the stub warnings in OWriterTable::refreshColumns().

Change-Id: I2dd43777a00a6958548e3dc8119c5cb825ebb02e
Reviewed-on: https://gerrit.libreoffice.org/40091Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>