Merge pull request #3072 from k8s-infra-cherrypick-robot/cherry-pick-…

…3063-to-release-1.6

[release-1.6] Fixing panic on AzureMachinePool creation with auto-scale

azure/scope/managedmachinepool.go

@@ -290,6 +290,9 @@ func (s *ManagedMachinePoolScope) SetCAPIMachinePoolReplicas(replicas *int32) {
 
 // SetCAPIMachinePoolAnnotation sets the specified annotation on the associated MachinePool.
 func (s *ManagedMachinePoolScope) SetCAPIMachinePoolAnnotation(key, value string) {
+	if s.MachinePool.Annotations == nil {
+		s.MachinePool.Annotations = make(map[string]string)
+	}
 	s.MachinePool.Annotations[key] = value
 }