fix crash related to hyperlink export, related #i20491#
fix crash related to hyperlink export, related #i20491#

Export of ooo20491-7.ods as xlsx

Change-Id: I43e1fd6dcb4bfbefea68c0b0a24c7ad0890d9efb

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