Fix ImportError: No module named pyparsing error in make build

Resolves #5

`pip install --upgrade pip` didn't work.

Relevant reading: puckel/docker-airflow#62

Dockerfile.template

@@ -48,6 +48,8 @@ RUN set -ex \
     && locale-gen \
     && update-locale LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 \
     && useradd -ms /bin/bash -d ${AIRFLOW_HOME} airflow \
+    && pip uninstall setuptools \
+    && pip install setuptools==33.1.1 \
     && pip install pytz==2015.7 \
     && pip install cryptography \
     && pip install pyOpenSSL \

Makefile

@@ -82,4 +82,4 @@ browse-web:
 	minikube service web -n $(NAMESPACE)
 
 browse-flower:
-	minikube service flower -n $(NAMESPACE)
+	minikube service flower -n $(NAMESPACE)