Fixed problem when get_password decorator destroys function it decorates

[ntrifunovic]

Code below wont work without this fix,
because decorator returns None

users = {
    "admin": "admin"
}
@auth.get_password
def get_pw(username):
    if username in users:
        return users[username]
    return None

get_pw("admin")

[miguelgrinberg]

Thanks!