Dockerfile: Replace javamelody URL with own-branch

The CI path to that jar changed from a master job to an own-branch one.

Change-Id: I6e90283049b2a8d1f6d04f5993a9e4de1c9a703a
diff --git a/src/test/docker/gerrit/Dockerfile b/src/test/docker/gerrit/Dockerfile
index f60212b..689d2b7 100644
--- a/src/test/docker/gerrit/Dockerfile
+++ b/src/test/docker/gerrit/Dockerfile
@@ -10,7 +10,7 @@
 
 USER gerrit
 
-ADD --chown=gerrit:gerrit $GERRIT_CI_URL/plugin-javamelody-bazel-master-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/javamelody/javamelody.jar /var/gerrit/plugins/javamelody.jar
+ADD --chown=gerrit:gerrit $GERRIT_CI_URL/plugin-javamelody-bazel-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/javamelody/javamelody.jar /var/gerrit/plugins/javamelody.jar
 ADD --chown=gerrit:gerrit $GERRIT_CI_URL/plugin-high-availability-bazel-$GERRIT_BRANCH/lastSuccessfulBuild/artifact/bazel-bin/plugins/high-availability/high-availability.jar /var/gerrit/plugins/high-availability.jar
 
 USER root