Bring partially https://github.com/gophercloud/gophercloud/pull/1221

Change-Id: I185e1991b68a22b387d043bc32bef79cd4c3dc4e
Related-To: PRODX-8893
diff --git a/openstack/orchestration/v1/stacks/errors.go b/openstack/orchestration/v1/stacks/errors.go
index 01f4f94..aa8cee6 100644
--- a/openstack/orchestration/v1/stacks/errors.go
+++ b/openstack/orchestration/v1/stacks/errors.go
@@ -31,3 +31,11 @@
 func (e ErrInvalidTemplateFormatVersion) Error() string {
 	return fmt.Sprintf("Template format version not found.")
 }
+
+type ErrTemplateRequired struct {
+	gophercloud.BaseError
+}
+
+func (e ErrTemplateRequired) Error() string {
+	return fmt.Sprintf("Template required for this function.")
+}