coverity#735631 division by zero
coverity#735631 division by zero

Change-Id: I3082395b89c0ecc2ac754cf845ea7892ffea0a9b

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