coverity#1266484 rework to scrutinze mnLen
coverity#1266484 rework to scrutinze mnLen

Change-Id: I8fb6d555a7f7afe02b4c0297d3fe4e456ba41dd0

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