Upgrade maven to v3.6.1

Move to the standard Apache Maven distribution and install
the latest version for using in our builds.

Change-Id: I54e5baf36f0b9abb6aa6e79b27e161b39c1eed3f
diff --git a/jenkins-docker/slave-debian/Dockerfile b/jenkins-docker/slave-debian/Dockerfile
index a09badd..1365856 100644
--- a/jenkins-docker/slave-debian/Dockerfile
+++ b/jenkins-docker/slave-debian/Dockerfile
@@ -11,7 +11,6 @@
 COPY set-java.sh /usr/bin/
 
 RUN apt-get update && apt-get install -y \
-    maven \
     openssh-server \
     curl \
     git-core \
@@ -29,6 +28,12 @@
     gettext-base \
     && rm -rf /var/lib/apt/lists/*
 
+ADD http://www-eu.apache.org/dist/maven/maven-3/$MAVEN_VER/binaries/apache-maven-$MAVEN_VER-bin.tar.gz /usr/local
+
+RUN cd /usr/local && \
+    tar xfz apache-maven-$MAVEN_VER-bin.tar.gz && \
+    cd bin && ln -s ../apache-maven-$MAVEN_VER/bin/* .
+
 RUN useradd jenkins -d /home/jenkins -m -s /bin/bash
 RUN mkdir /home/jenkins/.ssh
 RUN chown -R jenkins:jenkins /home/jenkins/.ssh
diff --git a/jenkins-docker/slave-debian/Makefile b/jenkins-docker/slave-debian/Makefile
index 31aa654..9408f97 100644
--- a/jenkins-docker/slave-debian/Makefile
+++ b/jenkins-docker/slave-debian/Makefile
@@ -1,5 +1,6 @@
 NO_CACHE ?= false
 IMAGE=gerritforge/gerrit-ci-slave-debian
+MAVEN_VER=3.6.1
 
 build: build_stretch
 
@@ -14,7 +15,7 @@
 build_stretch:  id_rsa.pub
 	@echo "Building Docker for Debian:$(DEBIAN_VER)"
 	@echo "========================================"
-	cat Dockerfile | DEBIAN_VER=$(DEBIAN_VER) envsubst > Dockerfile-$(DEBIAN_VER)
+	cat Dockerfile | DEBIAN_VER=$(DEBIAN_VER) MAVEN_VER=$(MAVEN_VER) envsubst > Dockerfile-$(DEBIAN_VER)
 	docker build --no-cache=$(NO_CACHE) -f Dockerfile-$(DEBIAN_VER) -t ${IMAGE}:$(DEBIAN_VER) .
 
 publish_stretch: