Fix behaviour on cluster scaling

Added a predeployment task which disables vpn-agent so it doesn't affect main
deployment manifests during cluster scaling

Change-Id: Ie5df398953c7cfb0df994317e46e9f964db3399a
Closes-bug: #1470461

tasks.yaml

@@ -13,3 +13,10 @@
     puppet_manifest: puppet/manifests/controller.pp
     puppet_modules: puppet/modules:/etc/puppet/modules
     timeout: 720
+
+- role: ['primary-controller']
+  stage: pre_deployment
+  type: shell
+  parameters:
+    cmd: if [ -n "$(which pcs 2>/dev/null)" -a -n "$(pcs resource show p_neutron-vpn-agent 2>/dev/null)" ]; then pcs resource disable p_neutron-vpn-agent --wait=30; fi
+    timeout: 40