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/weave/templates/weave-net.yml.j2

@@ -114,6 +114,9 @@ items:
         metadata:
           labels:
             name: weave-net
+          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
@@ -224,8 +227,10 @@ items:
             seLinuxOptions: {}
           serviceAccountName: weave-net
           tolerations:
-            - effect: NoSchedule
-              operator: Exists
+            - operator: Exists
+            # Mark pod as critical for rescheduling (Will have no effect starting with kubernetes 1.12)
+            - key: CriticalAddonsOnly
+              operator: "Exists"
           volumes:
             - name: weavedb
               hostPath: