server/db_op: DBO_block_chain__list: update for __PARENT & __HEAD (was HEAD and Parent) labels
server/db_op: DBO_block_chain__list: update for __PARENT & __HEAD (was HEAD and Parent) labels

ozFri/rhizi,ozFri/rhizi,Rhizi/rhizi,Rhizi/rhizi,Rhizi/rhizi,Rhizi/rhizi,ozFri/rhizi,ozFri/rhizi