fix(pip): update location of pip installer

raw.github.com URLs have moved to raw.githubusercontent.com, and
wget was seeing a 301 (Moved Permanently) under the covers. curl
does not automatically follow such a redirect, so the URL change
caused an error for deis/tester, but was benign here.

Author: mboersma

Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && \
     apt-get install -yq python-dev libpq-dev libyaml-dev
 
 # install recent pip
-RUN wget -qO- https://raw.github.com/pypa/pip/1.5.4/contrib/get-pip.py | python -
+RUN wget -qO- https://raw.githubusercontent.com/pypa/pip/1.5.4/contrib/get-pip.py | python -
 
 # HACK: install git so we can install bacongobbler's fork of django-fsm
 RUN apt-get install -yq git