non-transactional changed tables couldn't be rolled back

If you insert or update a non transaction table out side of a transaction and then start
a transaction using a transaction table which is then rolled back you get the warning:

Warning (Code 1196): Some non-transactional changed tables couldn't be rolled back

This is because the "transaction.stmt.reset()" was not called after the first implicit transaction.

Example:
Start the server with --plugin-add=pbms

pbms_metadata is a non transaction system table.

drizzle> create table t4(c1 int) engine = "InnoDB";
drizzle> warnings
drizzle> delete from pbms_metadata;
drizzle> begin;
drizzle> insert into t4 values(2);
drizzle> rollback