Pip install awscli fails on OSX

The specific build: https://circleci.com/gh/mediapop/patontheback-mobile/200

- sudo pip install awscli

Fails beccause of some permission issue - or - because six can’t be uninstalled (not sure?). I’ve worked around it by using brew instead.

There are some weird permissions issues with the system python in OS X. I think this is the preferred method for installing things in OS X.