Update build script to use build-target docker

services/filestore/Dockerfile

@@ -1,24 +1,21 @@
-FROM node:8.9.1 as app
-
-COPY ./ /app
+FROM node:6.9.5 as app
 
 WORKDIR /app
 
-RUN npm install
+COPY package.json package-lock.json /app/
+
+RUN npm install --quiet
+
+COPY . /app
 
 RUN npm run compile:all
 
-FROM node:8.9.1
+FROM node:6.9.5
 
 COPY --from=app /app /app
 
 WORKDIR /app
-
-# All app and node_modules will be owned by root.
-# The app will run as the 'node' user, and so not have write permissions
-# on any files it doesn't need.
 RUN ./install_deps.sh
-
 USER node
 
 CMD ["node","app.js"]