Remove react 13 workaround since this has been fixed in react 14
Remove react 13 workaround since this has been fixed in react 14

This was a workaround that was needed but it works in our current 
Version of react as confirmed by manual testing as well as by the
close of this issue: 
https://github.com/facebook/react/issues/1398#ref-commit-ea089fd

Test plan:
* the am/pm selector should work correctly in the date time picker
  And should not log a 
`warning.js:45 Warning: Use the `defaultValue` or `value` props on 
<select> instead of setting `selected` on <option>.` error

Change-Id: Ide6961ea594eec55801b4ac9b986e0fc9a616171
Reviewed-on: https://gerrit.instructure.com/164551
Tested-by: Jenkins
Reviewed-by: Clay Diffrient <9dff2e5c98626d20d2848250c411e8009465bb87@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>
QA-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms