Fix python license checking and uninstall docutils on build

Dockerfile

@@ -77,12 +77,22 @@ RUN curl -fsSL -o /usr/local/bin/prometheus-aggregator https://github.com/coreos
     && chmod +x /usr/local/bin/prometheus-aggregator
 
 # Install python dependencies
+# docutils is a setup dependency of botocore required by s3transfer. It's under
+# GPLv3, and so should be removed.
 COPY requirements.txt requirements-tests.txt ./
 RUN virtualenv --distribute venv \
     && venv/bin/pip install -r requirements.txt \
     && venv/bin/pip install -r requirements-tests.txt \
+    && (venv/bin/pip uninstall -y docutils || echo "docutils is not installed") \
     && venv/bin/pip freeze
 
+# Check python dependencies for the GPL
+# Due to the following bug, pip results must be piped to a file before grepping:
+# https://github.com/pypa/pip/pull/3304
+RUN venv/bin/pip freeze | grep -v "^-e" | awk -F'==' '{print $1}' | xargs venv/bin/pip --disable-pip-version-check show > pipinfo.txt && \
+    test -z "$(cat pipinfo.txt | grep GPL | grep -v LGPL)" && \
+    rm pipinfo.txt
+
 # Install front-end dependencies
 COPY static/ package.json tsconfig.json webpack.config.js tslint.json yarn.lock ./
 RUN yarn install --ignore-engines
@@ -99,12 +109,7 @@ RUN adduser memcached --disabled-login --system
 
 WORKDIR $QUAYDIR
 
-# Check python dependencies for the GPL
-# Due to the following bug, pip results must be piped to a file before grepping:
-# https://github.com/pypa/pip/pull/3304
-RUN cat requirements.txt | grep -v "^-e" | awk -F'==' '{print $1}' | xargs venv/bin/pip --disable-pip-version-check show > pipinfo.txt && \
-    test -z "$(cat pipinfo.txt | grep GPL | grep -v LGPL)" && \
-    rm pipinfo.txt
+
 
 # JS compile
 COPY bill-of-materials.json bill-of-materials.json