nose2.main() doesn't discover tests in current module

With Python 2.7.6 on Windows, after `pip install nose2` it's not possible to use `nose2.main()` in unittest-style to run tests in current module.

I.e. the following module
```python
import nose2
import unittest


class TestLoader(unittest.TestCase):
    def test_alwaysGreen(self):
        self.assertTrue(True)

if __name__ == '__main__':
    # unittest.main()
    nose2.main()
```

yields no found tests when executed directly:
```

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK
```

The test gets discovered just fine when using `nose2 -t ".."` from console in module's directory.