message: comment why we send the empty string
diff: @@ -71,7 +71,7 @@ class PasswordLogin extends React.Component {
  ev.preventDefault();
  if (this.state.loginType === PasswordLogin.LOGIN_FIELD_PHONE) {
  this.props.onSubmit(
  - '',
  + '', // XXX: Synapse breaks if you send null here:
  this.state.phoneCountry,
  this.state.phoneNumber,
  this.state.password,
  