Fix error when no responses file is given

go/fake-http/fake-http.go

// Load loads responses from the YAML file at path.
func (rs *Responses) Load(path string) {
	if path == "" {
		return
	}
	responses, err := rs.loadFile(path)
	if err != nil {
		log.Printf("Error: Parsing %s: %s", path, err)