Removed empty array, since webpack 2 doesn't support them anymore.

[Gongreg]

Issue: Couldn't start RN storybook with Production environment.

What I did

Removed empty array, since that was breaking webpack.

How to test

https://github.com/wix/storybook-server - Try to run npm run start.

[storybookbot]

	Fails
🚫	PR is not labeled with one of: ["cleanup","breaking","feature","bug","documentation","maintenance","greenkeeper","other"]

Generated by 🚫 dangerJS

[codecov]

Codecov Report

Merging #1381 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1381      +/-   ##
==========================================
+ Coverage   14.35%   14.35%   +<.01%     
==========================================
  Files         201      201              
  Lines        4613     4612       -1     
  Branches      506      587      +81     
==========================================
  Hits          662      662              
+ Misses       3510     3458      -52     
- Partials      441      492      +51

Impacted Files	Coverage Δ
...ct-native/src/server/config/webpack.config.prod.js	0% <ø> (ø)	⬆️
addons/knobs/src/components/types/Number.js	8.06% <0%> (ø)	⬆️
app/react/src/server/babel_config.js	44.82% <0%> (ø)	⬆️
addons/knobs/src/components/types/Select.js	7.93% <0%> (ø)	⬆️
addons/info/src/components/PropVal.js	0% <0%> (ø)	⬆️
addons/knobs/src/components/WrapStory.js	12% <0%> (ø)	⬆️
lib/ui/src/modules/ui/components/layout/usplit.js	38.7% <0%> (ø)	⬆️
addons/knobs/src/components/PropField.js	10.86% <0%> (ø)	⬆️
app/react/src/server/build.js	0% <0%> (ø)	⬆️
lib/ui/src/libs/key_events.js	23.25% <0%> (ø)	⬆️
... and 23 more

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[danielduan]

Looks clean!

[ndelangen]

Looks clean, is this breaking in any way?