OlTransducer in hfst_lookup.py uses global name transducer instead of class member

Trying to use OlTransducer at all results in:

`````` ~
    File "/home/tapirine/src/Simple4All/scripts/tools/hfst_lookup.py", line 24, in analyse
        if transducer.analyze(string):
    NameError: global name 'transducer' is not defined
```~


Reported by: flammie
``````
