Fix flanneld_options

Change-Id: I7346c3edf600ce7be497ad6e133c01c9ee0c26cd
diff --git a/kubernetes/files/kube-addons/flannel/flannel.yml b/kubernetes/files/kube-addons/flannel/flannel.yml
index f06618b..6df6114 100644
--- a/kubernetes/files/kube-addons/flannel/flannel.yml
+++ b/kubernetes/files/kube-addons/flannel/flannel.yml
@@ -101,7 +101,7 @@
         args:
         - --ip-masq
         - --kube-subnet-mgr
-        {%- for option, value in master.network.flannel.flanneld_options.items() %}
+        {%- for option, value in master.network.flannel.get('flanneld_options', {}).items() %}
         - --{{ option }}={{ value }}
         {%- endfor %}
         resources: