fix for memory leak in _ma_scan_init_block_record() (Valgrind error): make Maria support multiple calls to rnd_init() without an rnd_end() call in between.
fix for memory leak in _ma_scan_init_block_record() (Valgrind error):
make Maria support multiple calls to rnd_init() without an rnd_end()
call in between.


storage/maria/ma_blockrec.c:
  as explained in sql/handler.h, multiple calls to rnd_init() without
  a rnd_end() in between, are possible, and engine must be prepared to
  that. So in _ma_scan_init_block_record(), we allocate a buffer
  only if we have not yet one.

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