func tokenCachePath(tenantID string) string {
	return filepath.Join(azureCredsPath(), fmt.Sprintf("%s.json", tenantID))
}
func tokenCachePath(tenantID string) string {
	return filepath.Join(azureCredsPath(), fmt.Sprintf("%s.json", tenantID))
}
// tokenCachePath returns the full path the OAuth 2.0 token should be saved at
// for given tenant ID.