FmGridControl:  handle non-existing properties
FmGridControl:  handle non-existing properties

Fix crash with unhandled exception requesting "Description".

Change-Id: I6b6cb61273fb042532ab63620729f4129239fe81

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