Fix memory leak
Fix memory leak

...and add---most likely necessary---null check

Change-Id: I3f31c20442c45ddfd98429347f5c2521597c1769

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