set. This has always worked because when flag is !=0 then
HA_VAR_LENGTH_KEY is always set. Therefore, a test case cannot
reveal a faulty behavior.

Fix for bug#23074: typo in myisam/sort.c


myisam/sort.c:
  fix typo. Nevertheless, it has worked as expected
  because when a bit in flag is set HA_VAR_LENGTH_KEY has
  been always set too. Actually, no problem exposed through
  DDL.