Switch to new style react-hot-loader import usage

See:
https://github.com/gaearon/react-hot-loader#getting-started
gaearon/react-hot-loader#1122

ui/intermittent-failures/App.jsx

@@ -1,6 +1,6 @@
 import React from 'react';
 import { HashRouter, Route, Switch, Redirect } from 'react-router-dom';
-import { hot } from 'react-hot-loader';
+import { hot } from 'react-hot-loader/root';
 
 import MainView from './MainView';
 import BugDetailsView from './BugDetailsView';
@@ -62,4 +62,4 @@ class App extends React.Component {
   }
 }
 
-export default hot(module)(App);
+export default hot(App);

ui/job-view/App.jsx

@@ -1,5 +1,5 @@
 import React from 'react';
-import { hot } from 'react-hot-loader';
+import { hot } from 'react-hot-loader/root';
 import SplitPane from 'react-split-pane';
 import pick from 'lodash/pick';
 import isEqual from 'lodash/isEqual';
@@ -366,4 +366,4 @@ class App extends React.Component {
   }
 }
 
-export default hot(module)(App);
+export default hot(App);

ui/login-callback/LoginCallback.jsx

@@ -1,6 +1,6 @@
 import React from 'react';
 import Icon from 'react-fontawesome';
-import { hot } from 'react-hot-loader';
+import { hot } from 'react-hot-loader/root';
 
 import AuthService from '../shared/auth/AuthService';
 import { webAuth, parseHash } from '../helpers/auth';
@@ -77,4 +77,4 @@ class LoginCallback extends React.PureComponent {
   }
 }
 
-export default hot(module)(LoginCallback);
+export default hot(LoginCallback);

ui/logviewer/App.jsx

@@ -1,5 +1,5 @@
 import React from 'react';
-import { hot } from 'react-hot-loader';
+import { hot } from 'react-hot-loader/root';
 import { LazyLog } from 'react-lazylog';
 import isEqual from 'lodash/isEqual';
 
@@ -249,4 +249,4 @@ class App extends React.PureComponent {
   }
 }
 
-export default hot(module)(App);
+export default hot(App);

ui/test-view/ui/App.jsx

@@ -1,6 +1,6 @@
 import React from 'react';
 import PropTypes from 'prop-types';
-import { hot } from 'react-hot-loader';
+import { hot } from 'react-hot-loader/root';
 import { BrowserRouter, Route, Switch } from 'react-router-dom';
 
 import Navigation from './Navigation';
@@ -50,4 +50,4 @@ App.defaultProps = {
   location: null,
 };
 
-export default hot(module)(App);
+export default hot(App);

ui/userguide/App.jsx

@@ -1,5 +1,5 @@
 import React from 'react';
-import { hot } from 'react-hot-loader';
+import { hot } from 'react-hot-loader/root';
 
 import UserGuideHeader from './UserGuideHeader';
 import UserGuideBody from './UserGuideBody';
@@ -15,4 +15,4 @@ const App = () => (
   </div>
 );
 
-export default hot(module)(App);
+export default hot(App);