Fix for #1078

Should resolve issue #1078.

While digging around the tests, I also found a bit of odd behavior.  The tests seem to allow one extra epoch of training on a model that has already reached max_epochs.  

 >   # Try training while already reached max_epochs, should stop after 1 epoch
 >   # on first continue_learning() call

From `pylearn2/termination_criteria/tests/test_init.py`:

```
    # Try training while already reached max_epochs, should stop after 1 epoch
    # on first continue_learning() call
    train_obj = produce_train_obj(new_epochs=False, model=train_obj.model)
    train_obj.main_loop()
    test_epochs(train_obj.model.monitor.get_epochs_seen(), N+1)
```

Is that behavior desirable?