Stop using WCT variable in docker images

Also rename agent-node-wct to agent-node.

Change-Id: Idfcad0fd59134a314e5711a6932957b874d7c3f5
diff --git a/jenkins-docker/Makefile b/jenkins-docker/Makefile
index f8539ef..ec02283 100644
--- a/jenkins-docker/Makefile
+++ b/jenkins-docker/Makefile
@@ -1,4 +1,4 @@
-AGENT_DIRS ?= agent-debian agent-chrome agent-node-wct agent-bazel-nocache agent-bazel agent-bazel-docker agent-sbt agent-mvn agent-release agent-python3 agent-jekyll agent-aws
+AGENT_DIRS ?= agent-debian agent-chrome agent-node agent-bazel-nocache agent-bazel agent-bazel-docker agent-sbt agent-mvn agent-release agent-python3 agent-jekyll agent-aws
 ALL_DIRS ?= server bazel-cache $(AGENT_DIRS)
 NO_CACHE ?= true