Make GIT_HEAD work on quay

.dockerignore

@@ -5,7 +5,6 @@ test/data/registry
 venv
 .git
 !.git/HEAD
-!.git/refs
 .gitignore
 Bobfile
 README.md

Dockerfile

@@ -54,10 +54,8 @@ RUN mkdir static/fonts static/ldn
 RUN venv/bin/python -m external_libraries
 RUN mkdir /usr/local/nginx/logs/
 
-# We exclude everything except .git/{HEAD,refs} in .dockerignore so we don't
-# leak data into the image layer.
-RUN cat ".git/$( cat .git/HEAD | cut -d' ' -f 2 )" > GIT_HEAD
-RUN rm -fr .git
+# TODO(ssewell): only works on a detached head, make work with ref
+RUN cat .git/HEAD > GIT_HEAD
 
 # Run the tests
 RUN TEST=true venv/bin/python -m unittest discover -f