Comment 3 for bug 1375048

Instead of installing testrepository everywhere,
this wraps ImportError in testr_command.py:

```python
try:
    from testrepository import commands
except ImportError as e:
    class commands(object):
        def __getattribute__(self, key):
            raise e
```

I haven't run the tests. This ImportError is causing other setup.py commands to fail.

Please, either:

* [(0)] add the testrepository dependency
* [(1)] delay the Import
* [(1)] wrap the ImportError