pkg/agent/agent.go
func (k *Keyring) RemoveKeyUsingFile(pubkey string) error {
	p, err := ioutil.ReadFile(pubkey)
	if err != nil {
		return err
	}

	key, _, _, _, _ := ssh.ParseAuthorizedKey(p)
	if err != nil {
		return err
	}

	return k.RemoveKey(key)
}
func (k *Keyring) RemoveKeyUsingFile(pubkey string) error {
	p, err := ioutil.ReadFile(pubkey)
	if err != nil {
		return err
	}

	key, _, _, _, _ := ssh.ParseAuthorizedKey(p)
	if err != nil {
		return err
	}

	return k.RemoveKey(key)
}
// RemoveKeyUsingFile removes an existing key from keyring given a file