when i run 'ionic cordova platform add ios' alway not stop, so can't stop...

_From @cdscawd on August 9, 2017 10:38_

```
cli packages:
@ionic/cli-plugin-cordova : 1.6.2
@ionic/cli-plugin-ionic-angular : 1.4.1
@ionic/cli-utils : 1.7.0
ionic (Ionic CLI) : 3.7.0

global packages:
Cordova CLI : 7.0.1

local packages:
@ionic/app-scripts : 2.1.3
Cordova Platforms : none
Ionic Framework : ionic-angular 3.6.0

System:
Node : v8.2.0
OS : macOS Sierra
Xcode : Xcode 8.3.3 Build version 8E3004b
ios-deploy : 1.9.1
ios-sim : 6.0.0
npm : 5.3.0
```
other～
```
npm mirror taobao
$ nrm test taobao
* taobao - 393ms
```

when i run 'ionic cordova platform add ios' alway not stop
$ ionic cordova platform add ios
> cordova platform add ios --save
⠙ Running command

it is ionic version problem?

_Copied from original issue: ionic-team/ionic#12624_