Remove unnecessary import from react-button example

[rjatkinson2]

import { action } from '@kadira/storybook' created an unused import.

[crashuniverse]

LGTM.

This also removes the only eslint problem.

> eslint src
  2:21  error  'action' is defined but never used  no-unused-vars
✖ 1 problem (1 error, 0 warnings)