s3transfer not excluded in zip file, causing compatibility issues

[stonemary]

Kappa excludes folders like boto3 by default in its packaging process. However, s3transfer is installed during the installation of boto3:

from https://github.com/boto/boto3/blob/1.4.4/requirements.txt -e git://github.com/boto/botocore.git@develop#egg=botocore -e git://github.com/boto/jmespath.git@develop#egg=jmespath -e git://github.com/boto/s3transfer.git@develop#egg=s3transfer nose==1.3.3 mock==1.3.0 wheel==0.24.0 unittest2==0.5.1; python_version == '2.6'

The folder, s3transfer is not excluded during the kappa installation process.

This causes compatibility issues when user has a boto3 version different from the current Lambda buildin, and uploads a function with kappa.

To reproduce:

• put a version A of boto3 that is different from the current AWS Lambda buildin version B
• use kappa to deploy a function
• now deployed function uses the s3transfer library from version A and other parts of boto3 from version B

[stonemary]

I will do a quick fix and push the pr with another fix.