Fix linting errors in standard 9.0 (#1333)

* Fix linting errors in standard 9.0

* Update lockfile

examples/with-custom-babel-config/pages/index.js

@@ -27,10 +27,13 @@ export default class MyLuckNo extends React.Component {
     // using babel-preset-stage-0
     const message = do {
       if (randomNo < 30) {
+        // eslint-disable-next-line no-unused-expressions
         'Do not give up. Try again.'
       } else if (randomNo < 60) {
+        // eslint-disable-next-line no-unused-expressions
         'You are a lucky guy'
       } else {
+        // eslint-disable-next-line no-unused-expressions
         'You are soooo lucky!'
       }
     }

server/on-demand-entry-handler.js

@@ -5,9 +5,9 @@ import { parse } from 'url'
 import resolvePath from './resolve'
 import touch from 'touch'
 
-const ADDED = Symbol()
-const BUILDING = Symbol()
-const BUILT = Symbol()
+const ADDED = Symbol('added')
+const BUILDING = Symbol('building')
+const BUILT = Symbol('built')
 
 export default function onDemandEntryHandler (devMiddleware, compiler, {
   dir,