Module variables do not seem to be re-evaluated with autoreload

Test case:

```python
#----------------------------------------------------
# foo/__init__.py

# blank

#----------------------------------------------------
# foo/bar.py

def say_hello():
return "hello"

def say_goodbye():
return "goodbye"

#----------------------------------------------------
# foo/baz.py
from .bar import say_hello, say_goodbye

_full = say_hello() + " and " + say_goodbye()

def say_all():
return _full

#----------------------------------------------------
# notebook.ipynb

%load_ext autoreload
%autoreload 2

from foo.baz import say_all

print(say_all())
```

If you change `say_hello` to return `hola` in `bar.py` after importing, the value of `_full` is never re-evaluated, so subsequent calls to `say_all` do not reflect the new value.