problem with try catch on ie8

environment
```
nodejs@8.1.1
babel-core@6.25.0
babel-preset-babili@0.1.4
babel-preset-env@1.5.2
```

test.js
```javascript
var babel = require('babel-core');
var env = require('babel-preset-env');
var babili = require('babel-preset-babili');
var t = babel.transformFileSync('code.js', {
presets: [[env,{"targets":{"browsers":"ie >= 7"}}],babili],
babelrc: false
});
console.log(t.code);
```

code.js
```javascript
function a(b){
try{
console.log(123);
} catch(e){}
b();
}
a(function(){
console.log(456);
});
```

command line
```
node test.js
```

output
```javascript
"use strict";function a(a){try{console.log(123)}catch(a){}a()}a(function(){console.log(456)});
```

the output code does not work in ie8