Merge pull request #774 from kubernetes-incubator/ant31-patch-2

check if calico_peer_rr is defined

roles/download/defaults/main.yml

@@ -150,7 +150,7 @@ downloads:
     container: true
     repo: "{{ calico_rr_image_repo }}"
     tag: "{{ calico_rr_image_tag }}"
-    enabled: "{{ peer_with_calico_rr }} and kube_network_plugin == 'calico'"
+    enabled: "{{ peer_with_calico_rr is defined and peer_with_calico_rr}} and kube_network_plugin == 'calico'"
   pod_infra:
     container: true
     repo: "{{ pod_infra_image_repo }}"