Remove unused env variables

Change-Id: I51784638bcfc0d72af8bb808afa39985caa18d9d
diff --git a/example-setup/Dockerfile b/example-setup/Dockerfile
index 260bf7b..cf6d068 100644
--- a/example-setup/Dockerfile
+++ b/example-setup/Dockerfile
@@ -5,8 +5,6 @@
 RUN yum install -y gettext
 
 ARG JAVA_OPTS='--add-opens java.base/java.net=ALL-UNNAMED --add-opens java.base/java.lang.invoke=ALL-UNNAMED'
-ARG GERRIT_BRANCH=stable-3.5
-ARG LAST_BUILD=lastSuccessfulBuild/artifact/bazel-bin/plugins
 
 RUN  java $JAVA_OPTS -jar /var/gerrit/bin/gerrit.war init --batch --install-all-plugins -d /var/gerrit && \
     java $JAVA_OPTS -jar /var/gerrit/bin/gerrit.war reindex -d /var/gerrit