Docker tests: download JavaMelody from stable-3.12 build job

Change-Id: Ib16777033b1137989b195cee91ff1c043bd2db6e

src/test/docker/gerrit/Dockerfile

diff --git a/src/test/docker/gerrit/Dockerfile b/src/test/docker/gerrit/Dockerfile
index ebb4b84..66c0a38 100644
--- a/src/test/docker/gerrit/Dockerfile
+++ b/src/test/docker/gerrit/Dockerfile
@@ -27,7 +27,7 @@
     /tmp/gerrit.war
 
 ADD --chown=gerrit \
-    "https://gerrit-ci.gerritforge.com/view/Plugins-master/job/plugin-javamelody-bazel-master-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/javamelody/javamelody.jar" \
+    "https://gerrit-ci.gerritforge.com/view/Plugins-master/job/plugin-javamelody-bazel-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/javamelody/javamelody.jar" \
     /var/gerrit/plugins/javamelody.jar
 
 ADD --chown=gerrit \