SwDoc::DeleteRangeImplImpl: don't touch fieldmarks when undo is not available
SwDoc::DeleteRangeImplImpl: don't touch fieldmarks when undo is not available

Change-Id: Ia7fa4510a874a518c8bff3614a38425ee7802ad8

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