message: Fix specifying custom server for registration
  Broken by
  (ServerConfig interface changed but Registration not updated)
diff: @@ -123,18 +123,17 @@ module.exports = React.createClass({
  }
  },
  - onHsUrlChanged: function(newHsUrl) {
  - this.setState({
  - hsUrl: newHsUrl,
  - });
  + onServerConfigChange: function(config) {
  + let newState = {};
  + if (config.hsUrl !== undefined) {
  + newState.hsUrl = config.hsUrl;
  + }
  + if (config.isUrl !== undefined) {
  + newState.isUrl = config.isUrl;
  + }
  + this.setState(newState, function() {
  this._replaceClient();
  - },
  -
  - onIsUrlChanged: function(newIsUrl) {
  - this.setState({
  - isUrl: newIsUrl,
  });
  - this._replaceClient();
  },
  _replaceClient: function() {
  @@ -390,8 +389,7 @@ module.exports = React.createClass({
  customIsUrl={this.props.customIsUrl}
  defaultHsUrl={this.props.defaultHsUrl}
  defaultIsUrl={this.props.defaultIsUrl}
  - onHsUrlChanged={this.onHsUrlChanged}
  - onIsUrlChanged={this.onIsUrlChanged}
  + onServerConfigChange={this.onServerConfigChange}
  delayTimeMs={1000}
  />
  </div>
  