Zappa is ignoring some files and modules from installed packages

Context

I've noticed that Zappa is ignoring certain files during packaging. I believe this issue is caused as we are trying to exclude packages already builtin to the python lambda environment namely

 exclude = [
    "boto3",
    "dateutil",
    "botocore",
    "s3transfer",
    "six.py",
    "jmespath",
    "concurrent"
]

If any of the other python packages have any of the files or subfolders with the above names those are getting excluded as well. I noticed this as I was getting an ImportError while trying to do this from django.utils import six

Expected Behavior

The above mentioned patterns should only be ignored if they are in the root level virtualenv's site-packages but not as sub-module of some other package.

Actual Behavior

These patterns are being excluded at all levels.

Possible Fix

Copying everything and removing these files in a later step or updating the patterns.

Steps to Reproduce

1. Install django==1.11.6, zappa==0.45.1 in virtualenv
2. Create some zappa configuration without exclude argument
3. Ensure that there are no compiled files. (If there are compiled files from django.utils import six will not show an error as six.pyc would be available.)
4. Run zappa package env
5. Inspect the package for file django/utils/six.py

Environment

• Zappa version used: 0.45.1
• Operating System and Python version: Ubuntu 16.04, Python 2.7.12