message: RegistrationForm: the Fields are controlled, fix default values
diff: Copyright 2015, 2016 OpenMarket Ltd
  Copyright 2017 Vector Creations Ltd
  Copyright 2018, 2019 New Vector Ltd
  +Copyright 2019 Michael Telatynski <7t3chguy@gmail.com>
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  @@ -69,10 +70,10 @@ module.exports = React.createClass({
  fieldValid: {},
  // The ISO2 country code selected in the phone number entry
  phoneCountry: this.props.defaultPhoneCountry,
  - username: "",
  - email: "",
  - phoneNumber: "",
  - password: "",
  + username: this.props.defaultUsername || "",
  + email: this.props.defaultEmail || "",
  + phoneNumber: this.props.defaultPhoneNumber || "",
  + password: this.props.defaultPassword || "",
  passwordConfirm: "",
  passwordComplexity: null,
  passwordSafe: false,
  @@ -90,7 +91,7 @@ module.exports = React.createClass({
  }
  const self = this;
  - if (this.state.email == '') {
  + if (this.state.email === '') {
  const haveIs = Boolean(this.props.serverConfig.isUrl);
  let desc;
  @@ -455,7 +456,6 @@ module.exports = React.createClass({
  ref={field => this[FIELD_EMAIL] = field}
  type="text"
  label={emailPlaceholder}
  - defaultValue={this.props.defaultEmail}
  value={this.state.email}
  onChange={this.onEmailChange}
  onValidate={this.onEmailValidate}
  @@ -469,7 +469,6 @@ module.exports = React.createClass({
  ref={field => this[FIELD_PASSWORD] = field}
  type="password"
  label={_t("Password")}
  - defaultValue={this.props.defaultPassword}
  value={this.state.password}
  onChange={this.onPasswordChange}
  onValidate={this.onPasswordValidate}
  @@ -483,7 +482,6 @@ module.exports = React.createClass({
  ref={field => this[FIELD_PASSWORD_CONFIRM] = field}
  type="password"
  label={_t("Confirm")}
  - defaultValue={this.props.defaultPassword}
  value={this.state.passwordConfirm}
  onChange={this.onPasswordConfirmChange}
  onValidate={this.onPasswordConfirmValidate}
  @@ -512,7 +510,6 @@ module.exports = React.createClass({
  ref={field => this[FIELD_PHONE_NUMBER] = field}
  type="text"
  label={phoneLabel}
  - defaultValue={this.props.defaultPhoneNumber}
  value={this.state.phoneNumber}
  prefix={phoneCountry}
  onChange={this.onPhoneNumberChange}
  @@ -528,7 +525,6 @@ module.exports = React.createClass({
  type="text"
  autoFocus={true}
  label={_t("Username")}
  - defaultValue={this.props.defaultUsername}
  value={this.state.username}
  onChange={this.onUsernameChange}
  onValidate={this.onUsernameValidate}
  