fix(client): don't override protocol for socket connection to 127.0.0.1

Chrome and Firefox accept `http://`/`ws://` mixed-content connection to
`127.0.0.1` even when the actual website is loaded via `https://`.

Fixes webpack#2302

client-src/default/utils/createSocketUrl.js

@@ -50,6 +50,7 @@ function createSocketUrl(resourceQuery) {
   // because the browser doesn't accept non-secure websockets.
   if (
     hostname &&
+    hostname !== '127.0.0.1' &&
     (self.location.protocol === 'https:' || urlParts.hostname === '0.0.0.0')
   ) {
     protocol = self.location.protocol;