Ensure Spec.ProviderID is not empty string

If the Spec.ProviderID field is present but an empty string,
we may encounter issues.  This is particularly the case in
DR scenarios when a user is attempting to copy an existing
machine in attempt to create one.

pkg/actuators/machine/actuator.go

@@ -434,7 +434,7 @@ func (a *Actuator) Update(context context.Context, cluster *clusterv1.Cluster, m
 	// Parent controller should prevent this from ever happening by calling Exists and then Create,
 	// but instance could be deleted between the two calls.
 	if existingLen == 0 {
-		if machine.Spec.ProviderID != nil && (machine.Status.LastUpdated == nil || machine.Status.LastUpdated.Add(requeueAfterSeconds*time.Second).After(time.Now())) {
+		if machine.Spec.ProviderID != nil && *machine.Spec.ProviderID != "" && (machine.Status.LastUpdated == nil || machine.Status.LastUpdated.Add(requeueAfterSeconds*time.Second).After(time.Now())) {
 			glog.Infof("%s: Possible eventual-consistency discrepancy; returning an error to requeue", machine.Name)
 			return &clustererror.RequeueAfterError{RequeueAfter: requeueAfterSeconds * time.Second}
 		}
@@ -507,7 +507,7 @@ func (a *Actuator) Describe(cluster *clusterv1.Cluster, machine *machinev1.Machi
 		return nil, err
 	}
 	if len(instances) == 0 {
-		if machine.Spec.ProviderID != nil && (machine.Status.LastUpdated == nil || machine.Status.LastUpdated.Add(requeueAfterSeconds*time.Second).After(time.Now())) {
+		if machine.Spec.ProviderID != nil && *machine.Spec.ProviderID != "" && (machine.Status.LastUpdated == nil || machine.Status.LastUpdated.Add(requeueAfterSeconds*time.Second).After(time.Now())) {
 			glog.Infof("%s: Possible eventual-consistency discrepancy; returning an error to requeue", machine.Name)
 			return nil, &clustererror.RequeueAfterError{RequeueAfter: requeueAfterSeconds * time.Second}
 		}