OUString: use isEmpty instead of getLength()==0
OUString: use isEmpty instead of getLength()==0

Change-Id: Iaabfc2fb1f3fdf40681959232dbd7b02b333b877

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