branches/zip: buf_block_set_state(): Allow the state transition from BUF_BLOCK_READY_FOR_USE to BUF_BLOCK_NOT_USED.
branches/zip: buf_block_set_state(): Allow the state transition from
BUF_BLOCK_READY_FOR_USE to BUF_BLOCK_NOT_USED.

ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,ollie314/server,ollie314/server,ollie314/server,davidl-zend/zenddbi,flynn1973/mariadb-aix,natsys/mariadb_10.2,ollie314/server,ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,flynn1973/mariadb-aix,slanterns/server,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,davidl-zend/zenddbi,flynn1973/mariadb-aix,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,ollie314/server,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,ollie314/server,davidl-zend/zenddbi,davidl-zend/zenddbi,natsys/mariadb_10.2,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,davidl-zend/zenddbi,ollie314/server,davidl-zend/zenddbi