[t:3406], change comment in test of #3406

git-svn-id: file:///svn/mysql/tests/mysql-test@30435 c7de825b-a66e-492c-adef-691d508d4ae1

mysql-test/suite/tokudb.hotindex/t/hotindex-insert-2.test

-# test that deletes work when hot indexing is on
+# test that deletes work when hot indexing is on with replace into optimization
+# test is checking #3406
 
 set storage_engine='tokudb';