ci: support volume and custom branch

Signed-off-by: Noah Watkins <[email protected]>

docker/ci/entrypoint.sh

@@ -5,12 +5,21 @@ set -e
 mkdir /tmp/ceph
 bash /src/micro-osd.sh /tmp/ceph
 
+BRANCH=${branch:-master}
+
+apt-get install -y libprotobuf-dev protobuf-compiler
+
 # install zlog. this is done in the entry point so it will
 # pull the latest zlog source each time the container is run
 cd /src
-apt-get install -y libprotobuf-dev protobuf-compiler
-git clone https://github.com/noahdesu/zlog.git
+
+if [ ! -d /src/zlog/.git ]; then
+  git clone --branch=$BRANCH https://github.com/noahdesu/zlog.git
+fi
+
 cd zlog
+git status
+
 autoreconf -ivf
 ./configure
 make