Make parsing methods local

The parsing methods are used only internally; they must not be
exposed to users outside the respective packages.
diff --git a/openstack/orchestration/v1/stacks/utils_test.go b/openstack/orchestration/v1/stacks/utils_test.go
index 2f01c3b..6a3c5c0 100644
--- a/openstack/orchestration/v1/stacks/utils_test.go
+++ b/openstack/orchestration/v1/stacks/utils_test.go
@@ -17,7 +17,7 @@
 			"string_to_replace": "london bridge is falling down",
 		},
 	}
-	te.FixFileRefs()
+	te.fixFileRefs()
 	th.AssertEquals(t, string(te.Bin), `london bridge is falling down: my fair lady`)
 }