helm template cmd - conformity of output (#3811)

By changing a string from `##---` to `---` the output written to files matches the output generated to stdout.

cmd/helm/template.go

@@ -309,7 +309,7 @@ func writeToFile(outputDir string, name string, data string) error {
 
 	defer f.Close()
 
-	_, err = f.WriteString(fmt.Sprintf("##---\n# Source: %s\n%s", name, data))
+	_, err = f.WriteString(fmt.Sprintf("---\n# Source: %s\n%s", name, data))
 
 	if err != nil {
 		return err