Mitigate Meteor require warning.

[radekmie]

When antd is used in Meteor, this warning shows up:

Unable to resolve some modules:

  "indexof" in .../node_modules/component-classes/index.js (web.browser)

If you notice problems related to these missing modules, consider running:

  meteor npm install --save indexof

This PR aims to get rid of it.

[sholladay]

I have a simpler solution that works better with tools such as Rollup, which try to statically analyze the require() statements.

See: sholladay@adfdb84