fix crash on re-export of fdo39974-1.odt to odt
fix crash on re-export of fdo39974-1.odt to odt

Change-Id: Ib4246987a3665f655ad44339ade0350b074c3266

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core