Fix document about IE catch issue

Hi, I've found a mistake on README.

IE 9 can use [promise.catch](http://jsbin.com/corahuhu/1/edit "JS Bin - Collaborative JavaScript Debugging").
(IE Version 9.0.8112.16421 [modern.IE](http://modern.ie/ja-jp "modern.IE"))

[![ie9 - win7 snapshot 1 2014-05-24 17-14-18 2014-05-24 17-14-41](https://cloud.githubusercontent.com/assets/19714/3074008/18809916-e31c-11e3-9d10-ffcec1820972.png)](http://jsbin.com/corahuhu/1/edit)
 
[![browser support](https://ci.testling.com/azu/promise-catch-error.png)](https://ci.testling.com/azu/promise-catch-error)

Result from [azu/promise-catch-error](https://github.com/azu/promise-catch-error "azu/promise-catch-error").