DDL locking issue

## Description

Locked session hanging for ever.

## Steps to reproduce

Node 1:

```
abba=# begin;
BEGIN
abba=*# drop table foo;
DROP TABLE
```

Node 2:

```
abba=# insert into foo values (1);
```

Hanging as expected, but then:

Node 1:

```
abba=*# commit;
COMMIT
```

Insert on Node 2 still hanging and never ends.