manage default value for 'peer_with_router' var

roles/network_plugin/tasks/calico.yml

@@ -38,7 +38,7 @@
 
 - name: Calico | Disable node mesh
   shell: calicoctl bgp node-mesh off
-  when: peer_with_router and inventory_hostname in groups['kube-node']
+  when: peer_with_router is defined and peer_with_router and inventory_hostname in groups['kube-node']
 
 - name: Calico | Configure peering with router(s)
   shell: calicoctl node bgp peer add {{ item.router_id }} as {{ item.as }}