autoscaler: Set imagePullPolicy: IfNotPresent

We don't want to pull public container images that already exist.  This
creates prevents pods from starting if there is any connectivity issue
with the upstream registry.

autoscaler/kustomization.yaml

@@ -22,6 +22,7 @@ patches:
         spec:
           containers:
           - name: cluster-autoscaler
+            imagePullPolicy: IfNotPresent
             command:
             - ./cluster-autoscaler
             - --v=4