Use `react-native` instead of `React` on hmr config

Summary:Check https://github.com/facebook/react-native/issues/6640 for details
Closes https://github.com/facebook/react-native/pull/6696

Differential Revision: D3109128

fb-gh-sync-id: b80ff44f0dbc063870dc1dc7de9bf3c814ac9a12
fbshipit-source-id: b80ff44f0dbc063870dc1dc7de9bf3c814ac9a12

babel-preset/configs/hmr.js

@@ -25,7 +25,7 @@ module.exports = function(options, filename) {
         {
           transforms: [{
             transform: transform,
-            imports: ['React'],
+            imports: ['react-native'],
             locals: ['module'],
           }]
         },