"temporary table with data directory option fails"
  myisam should not use user-specified table name when creating
  temporary tables and use generated connection specific real name.
  Test included.


myisam/mi_create.c:
  Bug#8706
    When creating a temporary table with directory override, ensure that
    the real filename is using the hidden temporary name otherwise
    multiple clients cannot have same named temporary tables without
    conflict.
mysql-test/r/myisam.result:
  Bug#8706
    Test for bug
mysql-test/t/myisam.test:
  Bug#8706
    Test for bug