coreos-cincinnati: remove image value from spec.containers

During recent migration to deployment, the oc command:
`sudo rbac-playbook -l os_control_stg openshift-apps/coreos-cincinnati.yml`
returns an error:

```
"stderr": "The Deployment \"coreos-cincinnati\" is invalid: \n*
spec.template.spec.containers[0].image: Required value
```

This PR aims to fix the above.

roles/openshift-apps/coreos-cincinnati/templates/deployment.yml.j2

@@ -26,7 +26,6 @@ spec:
     spec:
       containers:
         - name: fcos-graph-builder
-          image: ""
           args: [
             "/usr/local/bin/fcos-graph-builder",
             "-v",
@@ -37,7 +36,6 @@ spec:
               mountPath: /etc/cincinnati/
               readOnly: true
         - name: fcos-policy-engine
-          image: ""
           args: [
             "/usr/local/bin/fcos-policy-engine",
             "-v",