pkg/asset/machines/userdata: Remove empty line from user-data YAML

This may have been what was giving us errors like:

  Sep 10 19:41:16 ip-10-0-3-146 bootkube.sh[1605]: "99_openshift-cluster-api_master-user-data-secret.yaml": unable to convert asset "99_openshift-cluster-api_master-user-data-secret.yaml" to unstructed
  Sep 10 19:41:16 ip-10-0-3-146 bootkube.sh[1605]: "99_openshift-cluster-api_worker-user-data-secret.yaml": unable to convert asset "99_openshift-cluster-api_worker-user-data-secret.yaml" to unstructed

after failing this cast to *unstructured.Unstructured [2].  I don't
have a theory for why a leading empty line would matter, but it was
the only thing that stuck at me when eyeballing the user-data
manifests.

[1]: openshift#1381 (comment)
[2]: https://github.com/openshift/library-go/blob/7d4acc018c610623ee1413b1e7aebe2ac675d35f/pkg/assets/create/creater.go#L264

pkg/asset/machines/userdata.go

@@ -8,8 +8,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-var userDataListTmpl = template.Must(template.New("user-data-list").Parse(`
-kind: List
+var userDataListTmpl = template.Must(template.New("user-data-list").Parse(`kind: List
 apiVersion: v1
 metadata:
   resourceVersion: ""