Fixed docker image build on script/robot-release script (cloudendpoin…

…ts#397)

* Upgrade docker to the latest version

Signed-off-by: Jae Kim <jaebong.kim@gmail.com>

* Reverted latest docker image build changes

* Merged sed commands

* Reverted unnecessary changes

script/linux-build-docker

@@ -61,6 +61,8 @@ if [[ "${PLATFORM}" == "flex" ]]; then
   # Update the Dockerfile to use local deb image
   DIMG="endpoints-runtime.deb"
   sed -i -e "s|endpoints-runtime||" \
+      -e 's|ARG BASE_IMAGE_TAG=latest||' \
+      -e 's|${BASE_IMAGE_TAG}|latest|' \
       -e "s|EXPOSE 8080|\nADD ${DIMG} ${DIMG}\nRUN apt-get update --fix-missing -qq \&\& \\\ \n    apt-get install -qqy python \&\& \\\ \n    dpkg -i /${DIMG}\n&|" \
       "$FLEX_DIR/nginx_proxy/Dockerfile"
   DOCKERFILE_PATH="$FLEX_DIR/nginx_proxy"