Apply cloud labels into ELB

Fixes #2048

tests/integration/update_cluster/complex/kubernetes.tf

@@ -228,6 +228,8 @@ resource "aws_elb" "api-complex-example-com" {
   tags = {
     KubernetesCluster = "complex.example.com"
     Name              = "api.complex.example.com"
+    Owner             = "John Doe"
+    "foo/bar"         = "fib+baz"
   }
 }
 

upup/pkg/fi/cloudup/utils.go

@@ -80,6 +80,9 @@ func BuildCloud(cluster *kops.Cluster) (fi.Cloud, error) {
 			}
 
 			cloudTags := map[string]string{awsup.TagClusterName: cluster.ObjectMeta.Name}
+			for k, v := range cluster.Spec.CloudLabels {
+				cloudTags[k] = v
+			}
 
 			awsCloud, err := awsup.NewAWSCloud(region, cloudTags)
 			if err != nil {