Declare the jenkins_worker_key_url so we can use it.

util/packer/jenkins_worker.json

@@ -9,7 +9,8 @@
     "test_platform_version": "{{env `TEST_PLATFORM_VERSION`}}",
     "security_group": "{{env `AWS_SECURITY_GROUP`}}",
     "delete_or_keep": "{{env `DELETE_OR_KEEP_AMI`}}",
-    "remote_branch": "{{env `REMOTE_BRANCH`}}"
+    "remote_branch": "{{env `REMOTE_BRANCH`}}",
+    "jenkins_worker_key_url": "{{env `JENKINS_WORKER_KEY_URL`}}"
   },
   "builders": [{
     "type": "amazon-ebs",
@@ -58,7 +59,7 @@
     "command": ". {{user `venv_dir`}}/bin/activate && ansible-playbook",
     "inventory_groups": "jenkins_worker",
     "extra_arguments": [
-      "-e \"jenkins_edx_platform_version={{user `test_platform_version`}} NEWRELIC_LICENSE_KEY={{user `new_relic_key`}} initialize_replica_set=false mongo_configure_replica_set=false jenkins_worker_key_url='{{env `JENKINS_WORKER_KEY_URL`}}'\"",
+      "-e \"jenkins_edx_platform_version={{user `test_platform_version`}} NEWRELIC_LICENSE_KEY={{user `new_relic_key`}} initialize_replica_set=false mongo_configure_replica_set=false jenkins_worker_key_url='{{user `jenkins_worker_key_url`}}'\"",
       "-vvv"
       ]
   }, {