Fix Jenkins master image

The new latest version of the jenkins/jenkins image does not
contain java 8 anymore. Thus, we need to use an older version of
the image.

Change-Id: Ia9fe3d74bebf24f6d993ebfb17feaf1564306bac

jenkins-docker/master/Dockerfile

diff --git a/jenkins-docker/master/Dockerfile b/jenkins-docker/master/Dockerfile
index 7e4f9e2..628067e 100644
--- a/jenkins-docker/master/Dockerfile
+++ b/jenkins-docker/master/Dockerfile
@@ -1,14 +1,8 @@
-FROM jenkins/jenkins
+FROM jenkins/jenkins:${JENKINS_WAR_VER}
 
 USER root
 
-ARG JENKINS_WAR_VER=2.204.1
-ARG JENKINS_WAR_SHA=924d2c9fabfdcacee1bae757337a07d7599eaa35
-
-# could use ADD but this one does not check Last-Modified header
-# see https://github.com/docker/docker/issues/8331
-RUN curl -fsSL http://repo.jenkins-ci.org/public/org/jenkins-ci/main/jenkins-war/${JENKINS_WAR_VER}/jenkins-war-${JENKINS_WAR_VER}.war -o /usr/share/jenkins/jenkins.war \
-  && echo "$JENKINS_WAR_SHA  /usr/share/jenkins/jenkins.war" | sha1sum -c -
+RUN echo "$JENKINS_WAR_SHA  /usr/share/jenkins/jenkins.war" | sha1sum -c -
 
 # Override Jenkins start-up script
 RUN mv /usr/local/bin/jenkins.sh /usr/local/bin/run-jenkins.sh

jenkins-docker/master/Makefile

diff --git a/jenkins-docker/master/Makefile b/jenkins-docker/master/Makefile
index 058a938..0498bb2 100644
--- a/jenkins-docker/master/Makefile
+++ b/jenkins-docker/master/Makefile
@@ -53,9 +53,9 @@
 	chmod a+r id_rsa*
 
 build: id_rsa
+	 cat Dockerfile | JENKINS_WAR_VER=${JENKINS_WAR_VER} JENKINS_WAR_SHA=${JENKINS_WAR_SHA} envsubst \$$JENKINS_WAR_VER,\$$JENKINS_WAR_SHA > Dockerfile-subst
 	docker build --no-cache=$(NO_CACHE) \
-        --build-arg JENKINS_WAR_VER=${JENKINS_WAR_VER} \
-        --build-arg JENKINS_WAR_SHA=${JENKINS_WAR_SHA} -t ${IMAGE} .
+        -t ${IMAGE} -f Dockerfile-subst .
 
 publish:
 	docker push ${IMAGE}
@@ -76,4 +76,3 @@
           echo -e "\n${NAME} is *RUNNING*\n"
 
 .PHONY: clean image publish
-