All CNIs: support ANY toleration. (#3391)

Before, Nodes tainted with NoExecute policy did not have calico/weave Pod.
Network pod should run on all nodes whatever happens on a specific node.

Also always set the Pods to be critical.
Also remove deprecated scheduler.alpha.kubernetes.io/tolerations annotations.

roles/network_plugin/flannel/templates/cni-flannel.yml.j2

@@ -51,6 +51,9 @@ spec:
       labels:
         tier: node
         k8s-app: flannel
+      annotations:
+        # Mark pod as critical for rescheduling (Will have no effect starting with kubernetes 1.12)
+        scheduler.alpha.kubernetes.io/critical-pod: ''
     spec:
 {% if kube_version|version_compare('v1.11.1', '>=') %}
       priorityClassName: system-node-critical
@@ -108,9 +111,10 @@ spec:
           mountPath: /host/opt/cni/bin/
       hostNetwork: true
       tolerations:
-      - key: node-role.kubernetes.io/master
-        operator: Exists
-        effect: NoSchedule
+        - operator: Exists
+        # Mark pod as critical for rescheduling (Will have no effect starting with kubernetes 1.12)
+        - key: CriticalAddonsOnly
+          operator: "Exists"
       volumes:
         - name: run
           hostPath: