test(ensure-nodejs-fork): remove unnecessary var

Change-Id: I99254a3f90b2aaa76f3d36f4ff54e40b8f0b965e
diff --git a/zuul.d/test-jobs.yaml b/zuul.d/test-jobs.yaml
index e40803a..b86860b 100644
--- a/zuul.d/test-jobs.yaml
+++ b/zuul.d/test-jobs.yaml
@@ -35,5 +35,3 @@
     files:
       - roles/ensure-nodejs-fork/.*
       - playbooks/test-ensure-nodejs-fork.yaml
-    vars:
-      role_name: ensure-nodejs-fork